The actress donned her skates alongside Lewis and Ellen Page for the roller derby film, which also marked her directorial debut.
But the 34 year old ended up nursing a painful leg injury when she took a nasty tumble.
She tells Britain's Empire magazine, "In one scene I wrestle Juliette Lewis. Her skate and both our body weights were on my thigh, so I ended up with a bruise a foot long and a foot wide. There's nothing hotter than a girl fight."