Talk about kicking a man (or teenager in this case) when he's down.

As if the singer hasn't got enough on his plate already with this 'Justin's totally the father of my unborn baby' business, now he's the subject of imitation and parody.

Last night in the good ol' Land of the U-S-of-A, Jimmy Fallon took the time to mimic 'the Biebz' with his in-house band and rap supergroup, The Roots. They should be expecting some angry hate mail from Justin's army of 'Bielibers' sometime this weekend.

We know the saying 'imitation is the sincerest form of flattery' but we're not sure how he's gonna take this video as a compliment. Hell of an addictive song though, much better than the original.