It's been a busy week for Justin Bieber, and friend Jimmy Fallon has never been one to let his accomplishments go unnoticed. Since Fallon has basically proven that he's what The Bieb will look like in 30 years, the late night host performed "(It's Not My) Baby" on his show Wednesday night, a spoof on Bieber's hit "Baby," reworked to incorporate details about the recent paternity rumors. Dressed in Bieber's leather jacket and metal dog tags, Fallon as Bieber takes the opportunity to warn the potential defamer Mariah Yeater how much a story like this could not only hurt his career, but his personal life ("You only did this to get my cash/And now Selena Gomez is going to kick my ass") as well as let everyone know that it was a whopping 45 seconds, not 30. Watch below as Fallon does his best to shuffle back and forth the only way the Canadian knows how, while Black Thought of The Roots serves as Ludacris equivalent, commemorating the potentially career-threatening ordeal as his "first sex." While we feel confident this will be another monster hit, we understand if Bieber needs a day or two before committing to including the track on Believe.