Liam Hemsworth was reportedly involved in a street fight in the early hours of Sunday morning (09.12.12).

The 'Hunger Games' actor - who is engaged to Miley Cyrus - was involved in an altercation outside a bar in Philadelphia when he confronted another man who he thought had thrown a rock at him and his friend.

In video footage posted on gossip website TMZ, the man is seen on the ground clinging to Liam's leg, before the actor punches him in the face and pushes his head down, while his pal helps hold the guy down.

Police arrived at the scene and dispersed the crowd, but no official reports have been filed.

Liam and his friend left and the unnamed man - who was bleeding - said: ''I don't think [Liam] fared much better.''

However, sources on the scene said that the 22-year-old actor - who was in the city working on new movie 'Paranoia' - was unhurt and that, despite his claims, no one saw a rock get thrown.

Calls made to Liam's representatives by TMZ have not been returned.