“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.” This is just a snippet of the rich conversation Bruno Mars and Rosé shared, being interviewed by Billboard.
Even over Zoom from across the world — Rosé in Seoul and Mars in Los Angeles — there’s a relaxed candor between the two collaborators and close friends. Rosé, 28, likens their bond to siblings, with Mars, 40, acting as both mentor and older-brother figure. They first met at an Atlantic Records-arranged meeting at Mars’ L.A. studio in the summer of 2024, as Rosé was preparing her solo debut album. Mars recalls how she was immediately “hustling information” from him. Rosé remembers: “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.’”
Rosé was determined to learn as much as possible about carving out her solo career. She signed with The Black Label for management in June 2024 and Atlantic Records for label services in September, later joining WME in September 2025 for worldwide representation. “I just remember feeling like a very curious soul as to what I would want to do on my own,” she explains. “So it was a good opportunity for me to meet new people in this industry” (Billboard).
Reuniting in L.A. with songwriter Amy Allen, who co-wrote her 2021 solo debut single “On the Ground,” and checking in with Omer Fedi, Rosé set out to create her solo debut album. But it was her meeting with Mars that spawned one of the biggest hits of 2025, their 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 the 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, “APT.” quickly became a global phenomenon. By early 2025, it had become the first No. 1 song by a K-pop artist on Billboard’s Pop Airplay chart, and in April, it set a record with its 19th week atop the Billboard Global Excl. U.S. chart, eventually topping the year-end editions of both that chart and the Billboard Global 200. Through November 27, the song had nearly 4.9 billion official on-demand global streams.
“I was like, ‘It’s about drinking? You got me,’ ” Mars recalls, laughing. But the song’s magic, he says, 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.’”
Their collaboration extended to the music video, where playful, offbeat ideas came to life. “I’d be like, ‘So the video, what do you think?’ And he would say these silly things and I didn’t think he was serious,” Rosé admits. Mars recounts the quirky props and costumes: “I ordered these Korean flags… I went to Japan and I bought these glasses, Rosie, I think you and me should wear these.” “Stop it,” she remembers thinking, though he was entirely serious.
Bruno also co-wrote and co-produced “Number One Girl.” He recalls: “I think it was the same thing, right, Rose? It was just like, ‘Hey, what do you think of this song?’” Rosé describes their process: “Then 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.”
Discussing the impact of “APT.”, Mars says: “To walk away with a win… we feel like we already won. The Grammys and any awards show, it’s a tricky situation… But the fact that this little idea turned into what it is and people did love it, that’s it. That’s when it’s done” (Billboard). Rosé adds, “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 learning from it as we speak.”
On the song’s appeal, Mars highlights its cultural resonance: “Because of Rosie, it’s a different thing… I really gravitated toward the song because it had a piece of Korean culture and I thought that was magical.” Rosé adds: “He has shown me and my culture so much love and appreciation… he really wanted to dive deep into that.”
“APT.” not only cemented Rosé’s solo success but also marked a milestone for K-pop on the global stage, showcasing how collaboration across cultures can produce music that resonates worldwide.
