Nicole Kidman has her latest movie role to thank for helping her shed the baby weight in a matter of weeks, according to a report.

In recent photos, the actress appears to have snapped back to her pre-pregnancy figure following the birth of daughter Sunday Rose in July.

An insider has revealed that the seemingly miraculous weight loss is down to stenuous exercise in preparation for her role in the film of the musical Nine.

"Nicole has been doing several hours of dance rehearsals each day and the weight has dropped off," says a source.

"Physically it's a very demanding role and the musical director, Paul Bogaev, has been living with Nicole and her family so they can train 24/7.

"The movie has an incredible cast and she knows it will do well at the Oscars - so wants to be sure she's in tip-top shape."