Kelly Osbourne is nursing a swollen ankle after she tripped onstage during filming of America's Got Talent.

Ozzy Osbourne's daughter paid a visit to the Los Angeles studio where the show is shot on Wednesday (15Aug12) to watch her mum Sharon in her role as a judge.

But as she leaped onto the stage to chat to her mother, clumsy Kelly took a tumble and was left in agony with a sore left leg.

In a series of posts on Twitter.com, she writes, "I tripped on the stage while visiting my Mumma at AGT. I have the worst luck it had to be in front of the whole audience!!! I have a golf ball on my ankle!"