Nicole Kidman has been forced to give up running after a nagging knee injury she picked up while making Moulin Rouge! turned jogging into a painful exercise.

The actress reveals she has turned to a stationary bike to get her heart rate up and work up a sweat.

She tells Shape magazine, "I tore cartilage in my knee while dancing in Moulin Rouge! (and) now I'm obsessed with spinning and I'm always trying to get people into it.

"It's such a quick work-out; if you can get to a class, it's done in 45 minutes and you feel great."