Rosé and Bruno Mars Spill Secrets Behind The Making of ‘APT.,’ 2025’s Biggest Global Hit

“I’m wearing my Rosie T-shirt,” Bruno Mars says with his signature suave smile as Rosé laughs in disbelief. She, too, is wearing artist merchandise — only hers is a Bruno Mars T-shirt. “We weren’t planning this,” attests Bruno, to which Rosé adds with a playful sigh, “This is our life.”

Even over Zoom today from across the world, with Rosé in Seoul and Mars in Los Angeles, there’s a comfortable candor between the two collaborators and close friends — a relationship that Rosé, 28, likens to siblings, with Mars, 40, acting as a music industry mentor and older-brother figure to her. They first met at an Atlantic-arranged meeting at Mars’ L.A. studio in the summer of 2024, as the Blackpink superstar was preparing her solo debut album, and Mars remembers how she was immediately “hustling information” from him. As Rosé recalls, “I was trying to get the most out of the meeting because I thought it’d be our last — first and last meeting, forever. Like, ‘This is my moment, I need to get all the tips, all the help I can.’

“There was a lot that I was determined to learn about,” she says of embarking on her solo career, for which she signed with The Black Label for management in June 2024 and Atlantic Records for label services that September — and, in September 2025, with WME for worldwide representation for future releases and solo global touring. “I just remember feeling like a very curious soul as to what I would want to do on my own,” Rosé explains, “so it was a good opportunity for me to meet new people in this industry.”

As she began working on the album that would become her solo debut, Rosie, she reunited in L.A. with songwriter Amy Allen, who co-wrote Rosé’s 2021 debut solo single, “On the Ground,” and vibe-checked Omer Fedi on a phone call while wrapping Blackpink’s Born Pink world tour in 2023. But it was her meeting with Mars that spawned one of the biggest hits of the 2020s, their punchy pop-rock collaboration “APT.”

“At the beginning, he really helped inspire me, not just even with ‘APT.’ but with the album,” Rosé says. (Mars also co-wrote and co-produced opening track “Number One Girl.”) “I had little questions and things that I couldn’t figure out… he was a big cheerleader for me at a very crucial moment.”

Released in October 2024 as Rosie’s lead single, “APT.” quickly caught fire. By the start of 2025, the hit had become the first No. 1 song by a K-pop artist on Billboard’s Pop Airplay chart, and in April, it scored a record-extending 19th week atop the Billboard Global Excl. U.S. chart — ultimately topping the year-end editions of the latter chart and the Billboard Global 200. The song had nearly 4.9 billion official on-demand global streams through Nov. 27, according to Luminate.

In September, “APT.” won song of the year at the MTV Video Music Awards — a first for a K-pop act — and in November, it earned three Grammy Award nominations, including for record and song of the year, making Rosé the first lead K-pop artist to be nominated in any of the Grammys’ main six categories. (She was in Seoul when the nominations were announced, having just gotten home from a night out to tune in at 12:50 a.m. her time. “I had just brushed my teeth and it happened,” she recalls with a laugh.)

But before “APT.” became a global smash, it was nothing more than Rosé’s favorite drinking game — and the “most straightforward and simple” one she could teach her musical collaborators, she says.

“I was like, ‘It’s about drinking? You got me,’ ” Mars says with a laugh. “But truthfully, it was Rosie’s voice, it was her saying this hook that just had this magic to it. And after talking to her it became, ‘Let’s build on this, let’s figure this puzzle out.’ That’s what all these songs are, right? And I thought it was beautiful that it was from her culture; she didn’t just send me a pop song talking about love or whatever. She really put me on game.”

What do you two remember about the first time you met?

Rosé: It was at his studio, and I walked in and Bruno was really, really nice to my team and I was all starstruck and then he started interviewing me. He was like, “So, I hear you’re doing an album” and whatnot. And then me being like, “Well, do you want to have a listen?” And I asked him the most random questions, like, (Addresses Mars.) what did I ask you? About management and…

Bruno Mars: It was very endearing. You know, coming from where she comes from in this humongous group, it was like, “I’m going to do it. I’m going to take a shot and try. Tell me something.” That’s what it felt like for me — it was a lot of pressure. And then we just started talking about music and what she wanted. Me just being curious was like, “How are you going to do this, coming from this gigantic group that means so much to people?” Rosie broke it down for me. I was very excited for her. And don’t get it twisted with the smiles and everything: She was very hungry. We became friends and that’s when everything began.

For the song and its music video, what were some ideas you built on with each other?

Rosé: I’d be like, “So the video, what do you think about the video?” And he would say these silly things and I didn’t think he was serious. I was really shocked to see how Bruno’s brain works. And I got so nervous, but to look back on everything and be like, “Wait, every little detail is these jokes we had along the way,” it was fun to see that all come together.

Mars: It’s very hard to explain… I ordered these Korean flags and she was like, “What?” And I was like, “I went to Japan and I bought these glasses, Rosie. I think you and me should wear these,” and she’s like, “Is he even for real?”

Rosé: On text it was like, “Rosie, we have to wear these big star glasses,” and I remember being like, “Stop it.” And he was serious the whole time, which is crazy.

Mars: You kept saying, “You’re going to make me pretty, right?”

Rosé: Yeah, yeah, yeah.

Mars: “You’re not going to make me look like a fool, right?”

Rosé: I think the only thing that didn’t happen was we were supposed to do these funny dance moves and at one point you were going to be on my back. I think that changed to the drum set.

Mars: That’s right. And Rosie was insane. I was like, “Rosie, go play the drums,” and she’s like, “Like this?” And I’m like, “Just like that.”

Did you teach her how to play the drums?

Rosé: A little.

Mars: But she’s got it. She’s a great dancer, so it kind of came natural for her when I was telling her, “OK, go one, two, one, two.” That was light work for her.

Rosé: Honestly, I went home and woke up the next day with a sore stomach because I was laughing so much throughout the whole video. Seriously, it was the most fun video shoot I’ve ever had.

Mars: Little did Rosie know there was a silent war going on between me and my boy Daniel [Ramos], who directed the video with me. We were under so much pressure because we were running out of time. We did this whole music video in slow motion, basically. That’s how it looks all jittery, so we had to do the song over and over again and it was going (Sings in slow motion.), “Apateu, apateu/Apateu, apateu.” So it’s hours and hours of that and everybody’s looking at us like, “What the hell are they doing?” And the song’s not even out yet, no one’s heard it. So we have a whole video set and Rosie’s team being like, “Are we going to be OK?” So as much fun as it was, there was a lot of trust.

Bruno, you also co-wrote and co-produced “Number One Girl.” At what point did you become involved in that song?

Mars: I think it was the same thing, right, Rose? It was just like, “Hey, what do you think of this song?”

Rosé: We were on a phone call regarding other work stuff and I said, “Bruno, I’m kind of stuck on this,” and he hears it and I remember he started playing it on the piano. Then he started singing it and he was like, “It should kind of do this and do that.” And I was like, “Whoa, whoa, whoa, slow down, let me write that down.” And the next day, he was like, “Come to the studio, let’s work on it a bit.” He showed me his ideas and it was really, I feel like, what the song needed. And yes, there was a little bit of debate in the middle of me being like, “But we can’t let go of this!” and him being like, “Rosie, you have to trust me.” But it was all for the better.

Are there other songs you two worked on that didn’t make it on this album — or that you’ve worked on since this album?

Rosé: (Laughs.)

Mars: Oh, yeah, there is. And we love that song that we worked on — I won’t say the title… We’re just trying to figure out when, or how.

Bruno, you said recently that “APT.” “birthed a new K-pop juggernaut named Bruno Mars.”

Mars: I don’t know if you know this, but it’s different for me now in Korea.

Tell me.

Mars: Because of Rosie, it’s a different thing. They treat me a little different now over there. And like I said, I really gravitated toward the song because it had a piece of Korean culture and I thought that was magical.

Rosé: I went to your concert [in June 2023] a year before I met you, and I think a big part of what makes the whole crowd fall in love with Bruno was that we all felt how passionate he was toward our culture. I was blown away. I’d never seen a concert where it was so catered to wherever he was. We were in Korea and he had written this whole song based on our…

Mars: I had to let these Korean girls know.

Rosé: He was letting them know! And as we were working on this song, he has shown me and my culture so much love and appreciation and acceptance; he really wanted to dive deep into that. He always reminds me, even now, how much we need to embrace the culture and how important it is and how that is what the people want to hear. They want to be introduced to this beautiful culture that we have.

Mars: No one says it, but I feel like Rosie is the first time we’ve seen this. The last time we’ve seen something to this effect was “Gangnam Style.” I still think that was an amazing thing to happen, this guy comes out and he’s talking about Gangnam style and the whole song is in Korean and that’s the learning lesson, the rock star-ness of that. This is what we do, this is how I talk, this is what we look like, this is how we’re dancing over here — and watch me sweep the nation with this s–t. And he did. “APT.” with Rosie, I’ve never felt this before, I’ve never seen this before, where Rosie is this Korean girl that introduced this thing to people who don’t know about it, including myself. And that’s been the most enjoyable part for me. Seeing everybody react… that is magic to watch.

Bruno, have you now taught the game to others?

Mars: Oh, yeah. I’m the “APT.” guy now, thanks to Rosie. I used to be the “Grenade” guy, but now I’m the “APT.” guy.

Other than Rosie, who is the best person you’ve played the game with?

Mars: I remember Rosie came to my club in Las Vegas… that’s when she was schooling everybody at the table on how to do this. She took it very serious. That’s the most memorable moment — and then we got wasted.

Bruno, as someone who has a lot of experience at the Grammys — especially in the categories of record and song of the year, which you’ve won twice and three times, respectively — why can “APT.” compete, and maybe even win?

Mars: To walk away with a win… This is tricky for me because I feel like we won [already]. The Grammys and any awards show, it’s a tricky situation, and you never know. But for me, the fact that this little idea turned into what it is and two artists got together and put it out and we weren’t crazy and people did love it, that’s it. That’s when it’s done. Did you do it or you didn’t? That’s the win. I’m not trying to be political, but that’s the truth, so anything else is a bonus. We get a chance to get dressed up and go have fun, and me and Rosie get to hang out at the Grammys. But you can’t tell me that we didn’t win already.

Rosé: That was such a good answer. You’re so good at interviews.

Will you two wear matching outfits to the Grammys?

Mars: Rosie’s not ready for that.

Rosé: Hey!

Mars: You’re not ready to take it there, because what I got imagined up in my head… the silhouette that I see me in…

Rosé: The last time we went to an event, that was all my idea, remember?

Mars: Rosie takes me to this event that was nuts. And I’m very…

Rosé: I gave him the full Korean experience.

Mars: I don’t know how to act in these situations and Rosie is like, “Don’t worry.” And Rosie walks me out to this stadium and we’re sitting in a box on a pedestal with a bunch of other artists, there’s people everywhere…

Rosé: I was laughing so much.

Mars: And she’s so calm and collected.

Rosé: When they saw you next to me sitting there, I was like, “What have I done to him?”

Mars: I was like, “You lied to me, Rosie. You said this was going to be easy.” (Laughs.)

What was this?

Mars: Exactly. It’s called the MAMA Awards and it’s held in Osaka [Japan]. So I’m thinking in my head, “The MAMA Awards, that sounds sweet and boutique and cool, I’m going to put a little suit on,” and we walk into this stadium and everybody is looking.

Rosé: We were exposed.

And it’s a big deal when Bruno steps out.

Rosé: It was! I felt really bad but deep down inside I was like, “This is the best thing of my life.”

When you both hear “APT.” now, what lyric stands out as a favorite?

Mars: “Kissy face, kissy face.” That’s it.

Rosé: “Don’t you want me like I want you baby.” That part has that pull, I think. There’s magic in that line.

Mars: Especially when I sing it. Yeah, Rosie?

Rosé: Yes. Yes, of course.

Bruno, your 2010 debut album has remained on the Billboard 200 for more than 750 weeks. When you think about an artist like Rosé, and others who are in her position, what would you say is the key to achieving longevity in this business?

Mars: We’re in the songwriting business and it’s not easy. It’s not easy to write a song that’s got the thing. But you can’t forget that it’s not going to happen everyday — you just got to be an antenna and be ready when it does. And that’s it. There’s no shortcut. And it all has to align; the song has to match the artist that has to match the presentation in order for the magical thing to happen. And good luck, because it’s almost impossible. That’s the hardest thing to do in our line of work: to be able to hit some kind of frequency that means something to people. Billions of songs have been written already, so you just have to be a student and show up to the studio and try every day — and one day the magical thing will happen.

How has this collaboration changed your careers?

Rosé: Even when we first wrote the song there was some part of me that was somewhat scared of the song. I could just see people react to it and come back to me like, “Can I hear that one more time?” I think I was a bit confused, and I wasn’t sure what that meant. And then to see what it’s become and to see what Bruno saw in it and then what the world saw in it, it’s proven to me what music means to people. I’m still trying to process it; I’m still learning from it as we speak.

Mars: I’m always trying to write something special. If I knew how to do it, I’d do it every day, and I don’t. But I keep going to the studio and I keep trying and trying, and I do know the feeling of when there’s some kind of magic happening… I got to work with some incredible people. Getting in the studio with Cirkut on this was amazing. I’d play the guitar and throw it to him and he’d do some crazy s–t with it on his laptop. Everybody [was] trying to execute this thing that we feel that we have. And that’s what I meant by winning, because that is just hard. Then being able to put that out, being able to share this song with Rosie in any capacity, being able to watch her do what she does and watch kids and adults sing this song, that’s it. Even if they don’t know what [“APT.”] means, they’re going to feel it, because that’s our job as musicians. And if we’re lucky, they’re going to deep dive into it: “What is this? What are they saying?” That’s the beauty of Rosie bringing this to the world. This is what going for it looks like. It’s a reminder that if it doesn’t feel like that, you’re probably not doing something right.

This story appears in the Dec. 13, 2025, issue of Billboard.