Colin Farrell was left with a real black eye after challenging Rosario Dawson to a fight on the set of 2004 movie ‘Alexander’.

The pair were shooting a battle scene, and Farrell asked Dawson to make it as realistic as possible.

She reveals: “He was all, ‘C’mon, you can hit me.’ I said, ‘All right, but I’m from New York, you know. Be careful what you ask for.’ So I smacked him, and pow!”
[Source]