Sad part: Sometimes it’s real

Keira Knightley

is brutally attacked by her boyfriend in a shocking new domestic violence ad for the British charity Women’s Aid.

The two-minute clip, which debuts in movie theaters Monday, opens with the actress, 24, heading home from a long day of filming.

When she gets home, her boyfriend verbally and physically attacks her because he thinks she’s having an affair with a co-star.

As the camera pans out, Knightley lays on the floor as the beating continues. The location is revealed to be an empty film set.

“Isn’t it time someone called cut?” the ad says.

“Atonement” director

Joe Wright