Beyonce Knowles beat up her co-star Ali Larter in her new film. The star plays a woman who has to defend her family from a crazed stalker, played by Ali, in new movie "Obsession" and she didn't hold back when the two actresses had to brawl.

Ali said: "Our fight scene was so fun! I'm glad it looked scary. We went all the way to make sure it looked real. I was bruised all over, scraped up. That's the fun of it! Neither of us are girls who phone things in."