Jackson Rathbone's Gaga Birthday

Twilight star Jackson Rathbone was caught up in Lady GaGa mania while out celebrating his birthday in Las Vegas - he found himself in a club surrounded by hundreds of impersonators.

The actor, who plays vampire Jasper Hale in the bloodsucker franchise, turned 25 on Monday and celebrated with a weekend trip to Sin City.

But his birthday celebrations took a bizarre twist on Friday night when the actor and his pals arrived at Bank nightclub only to find themselves caught up in the middle of a Lady Gaga impersonator competition.

The actor took it all in good humour and was spotted signing autographs and posing for pictures with dozens of Gaga lookalikes.

A source tells New York Post gossip column PageSix, "They (the impersonators) take it really seriously. People were going nuts. Especially when Jackson Rathbone showed up for his birthday."