Justin Bieber dropped his bumping new single "Boyfriend" on Monday (March 26), teasing his next album, Believe. It's a grinding, midtempo song that hears Bieber proclaiming all the ways he can make a girl happy (swag and fondue included!).

Co-produced and co-written by "Cooler Than Me" singer Mike Posner, the song shows growth from Bieber's "Baby" days. When MTV News caught up with Posner last week, he told us what it was like to hit the studio with Bieber (and co-producer and co-writer Mason Levy) for the track.

"I've known [Bieber's manager] Scooter [Braun] for a few years, so I actually ran into Scooter at a Clippers game and told him I would love to work with Justin," Posner said. "I got the opportunity to write with Justin. I didn't really know what to expect at first, but he's an incredible, incredible writer and amazing vocalist.

"Because I'm an artist myself, I can be pretty selective on who I produce for and who I make beats for ... and really what I'm looking for is an amazing vocalist, somebody that can sing better than I can," he continued. "And the other thing is somebody that's willing to not try to make something that succeeds within the matrix of what pop music is now, but makes something that moves that matrix to where it is, and Justin was willing to take that leap with me."

Bieber spoke to Ryan Seacrest on his radio show hours after the song's world premiere Monday, explaining why this was the perfect track to kick off the Believe era.

"It was a really hard choice. I mean, we had so many songs, so many uptempos we could release, [that] I thought, 'Let's slow it down,' " he said, adding that there are already plenty of fast songs all over the radio. "It's just something a little bit more mature, but it's also something I think I'm ready for."

While fans and industry insiders had been wondering what a more grown-up Bieber would sound like, he said he tried to block out all the noise when making the track. "There's so many people that are going to give me opinions, but I'm the only one who can ultimately make those decisions, because I'm going to have to live with my career for the rest of my life. So I thought this was the perfect single," he said, adding that this song "was me all the way; it is a representation of me."

And Bieber said "Boyfriend" perfectly sets up what's coming next. "It's kind of classic," he said of the album. "The songs, I feel, won't get old. The music is very fresh, but it's also — I'm taking a lot from old-school music, a lot of Michael Jackson, a lot of old R&B, a lot of old pop. It's pretty special."

What do you think of "Boyfriend"? Share your reviews in the comments below!