The 44-year-old actor halted shooting on Iron Man 2 and rushed to help the man, who had been injured during a scene.

A source said: "Robert charged into a live scene yelling, Cut! Cut! The extra was writhing on the ground in agony after a rampaging evil robot smashed him flat".

The extra had been involved in a sequence which saw a group of people running away from a group of robotic villains.

Although the man was accidentally hit by a stuntman in an iron costume, filming continued because no-one noticed he was in pain.

The source added: "Cameras kept cranking until Robert, who wasn’t in the scene, suddenly noticed one extra twisting in pain and moaning 'Help, I’ve broken something'".

Robert called for paramedics and comforted the man until they arrived.

The injured extra was taken to hospital, where he was diagnosed with a broken hip.