Nicole Kidman is overwhelmed by the pressure of juggling motherhood with her career. Friends are said to be worried about the actress - who gave birth to daughter Sunday Rose in July - after she slimmed down to 10lbs below her pre-pregnancy weight and collapsed in tears as the strain took its toll.

A source close to the 'Moulin Rouge!' star said: "From the start Nicole seemed determined to lose her baby weight. Just a week after giving birth she had regained her pre-pregnancy figure and dropped nearly all the weight she'd gained while expecting. "We think she has since dropped 10lbs below her pre-pregnancy weight of 125lbs.

"Nicole started rehearsals for new musical 'Nine' a few weeks after Sunday's birth. She's doing two or three hours of dancing a day. On top of that, she went right back to working out with a trainer, doing yoga and Pilates, as well as swimming and jogging."

Nicole showed her stress during a recent visit with husband Keith Urban to see her family in her home country of Australia. The source added: "They flew to Sydney for some family time but Nicole broke down in tears within a few hours of landing. She sounds like she's overwhelmed."