RADIO DISNEY - Justin Bieber stops by Radio Disney to debut his new single "Boyfriend." While in studio, he joins Candice to
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Mike Posner is quite the prolific dude. He made it big in 2010 with "Cooler Than Me," and recently had a resurgence with 2015's "I Took a Pill in Ibiza." In between, he wrote songs for other artists, and that includes the one and only Justin Bieber.

Yep, Posner penned Bieber's 2012 breakout "Boyfriend" with Mason D. Levy and Mat Musto. And like it goes in the music industry, a lot of songs get tossed around, making the final version a lot different from the initial idea.

When Posner visited The Tonight Show Starring Jimmy Fallon, he told the story about how he came up with the idea for "Boyfriend":

"The story starts on a dark Los Angeles night. I was hanging out with my friend Blackbear, and he was playing guitar, and I started singing this thing over it. Originally we had these lyrics that went, 'Inside of your bedroom, no one has to know. Inside of your bedroom, that's where we should go.'

"But I never really liked those lyrics and so I sat in the studio for hours, and then this statement popped into my head: 'If I was your boyfriend.'"

And there you have it!

Watch an interview with young Bieber below: