Wife of Ex-Beatle Paul McCartney has fallen over during dance practice with her dancing partner Apolo Anton Ohno, injuring her right leg.

The animal rights campaigner was practicing the quick step when she slipped and fell awkwardly onto the dance floor. Apparently her prosthetic leg was the cause of her fall when it became loose and she lost her balance and fell on her knee.

The fall follows Heather Mills’ first appearance on the show which brought in record numbers of viewers. Mrs Mills is the first ever contestant to appear on the American hit tv programme to have a prosthetic leg.

Heather Mills was taken to the city hospital and treated for a twisted ankle but returned to set three hours later. Her prosthetic leg was not damaged but according to a source, Heather Mills’ personal nurse was called onto set to adjust some fittings in order to ensure it didn’t happen again.

Heather was not thought to have sustained a serious injury during the fall and she resumed her dance training later that same day.

“I saw Heather fall and it didn’t look very good” said a member of the crew “One minute she was dancing around quite fast, then she just went down – it looked like a nasty fall but we’re all pleased she’s ok”.

More than 20 million  US viewers tuned in to see Heather Mills foxtrot on the dancefloor yesterday, the biggest audience ever for a season premiere of the ballroom dancing show and clearly the most watched show of the night on US television.

Ms Mills and her dancing partner Apolo Anton Ohno, danced the foxtrot to ‘Cheek to Cheek’ -  the Irving Berlin classic. The former model turned social activist, who lost her left leg below the knee in a 1993 traffic accident, seemed stiff as she danced in a long, pink and cream sequinned gown.

The judges liked her performance as did the studio audience and Heather Mills received a standing ovation.

"You've got more guts than Rambo," judge Bruno Tonioli enthused. Fellow judge Len Goodman called her "an inspiration". "I'm just glad I did not fall over."  Replied Heather.

Viewers will also vote on the couples dance effort along with the other 11 couples and the scores of these dances and next week’s dance off will determine who will be eliminated on next weeks show. Heather Mills and partner have gone from being odds on favorite to now 3^rd from top. The couple scroed 18 out of 30 points, which was higher than tallies received by several other teams.

world female boxing champion Laila Ali (daughter of Muhammad Ali), country music star Billy Ray Cyrus, former 'N Sync boyband member Joey Fatone and Olympic speedskater Apolo Anton Ohno are among the other contestants on the show.