British actress Keira Knightley spent her Christmas and New Year's holidays on her sofa after tearing a muscle in her thigh while filming a new movie.

The Atonement star hasn't named the project she was working on at the time of the mishap, but she admits the injury left her crippled for weeks.

She tells People magazine, "Over Christmas, I tore my quad muscle. I was filming, and I had to run through a door. I hadn't warmed up and it got very cold, and when I tried to run it just happened. I couldn't do very much until it healed."