Jonah Hill, of Superbad and Forgetting Sarah Marshall fame, was on talk show David Letterman Monday night, and shared his experience of how a Twitter user pretending to be him is slowly taking over his life.

He takes it on the chin though and sees the funny side, great stuff, but you can see how other celebs might just flip out over this kind of stuff, as there’s potentially serious implications.

Twitter recently implemented a “verified accounts” system after baseball manager Tony La Russa threatened to sue the company after someone pretended to be him on Twitter.