He's an extremely successful singer, first as part of 'N Sync and later on his own. Up through now he's won 6 Grammy and 2 Emmy awards. He's been in a handful of movies before, but I think the Social Network was the first I recognized him in.

[another pop-culture disconnectee here]: I wouldn't know the name if he had not instigated an infamous "wardrobe malfunction" at a superbowl (not that I actually watched the game/halftime).

He is Brittney's ex. Also remember the 'Cry me a river' song.