At the Billboard Music Awards last night, Post Malone and 21 Savage took home the 'Top Rap Song' for "Rockstar." Fresh off providing some ad-libs on Childish Gambino's "This Is America," 21 was having one hell of a celebratory night. On the red carpet, Billboard managed to catch up with 21 before the show, and he talked about how he celebrated "Rockstar" hitting the No. 1 spot on the Billboard Hot 100, and what it was like to collaborate with Donald Glover.

“Me and Childish just sat in the studio for like six hours and just talked the whole night, really," he told Billboard. "We made a song and I did some ad libs on that song, but we were really just talking the whole time. He a cool dude, and he from my city, so same side of town.” Providing extensive ad-libs to "This Is America," 21 has already built up a great working relationship with Glover, so hopefully, that means another collaboration between the two is on the way.

When asked about what he's working on himself, though, he teased that he's been working with Pharrell recently. He didn't offer a time-frame for when we should expect to hear the results of those studio sessions, but he did open up about his dream collaborations. "That’d be a dream come true to work with Beyoncé or Rihanna … I already did something with Nicki [Minaj], Cardi [B], so now it’s just Beyoncé and Rihanna and I’ll be good.”

As for how he celebrated achieving his first No. 1 single with "Rockstar," he explained, "I forgot. I think I got drunk, probably."