One of Zac Efron's fans pounded the window of his car so hard her hand bled.

The teen heartthrob was enjoying a meal in a cafe with his Me and Orson Welles co-star Claire Danes when he was spotted by a group of teenage girls.

Within seconds the girls were mobbing the 22-year-old, who was quickly escorted to a nearby police car. Despite the presence of armed law enforcement officers, the girls crowded around Zac's vehicle, with one banging it so hard her arms were covered in blood.

Claire said: "Zac was mobbed. He was escorted out in a police car and a girl bloodied her fist because she was pounding the glass of the window so forcefully. It's bananas. I feel lucky I never have to deal with that level of attention."

Zac recently revealed he was forced to use a secret tunnel to get from his hotel room to the set of Me and Orson Welles on the Isle of Man because his fans were so crazy.