But the Oscar-winning actress put a stop to those rumours abruptly yesterday as she left a gym in Los Angeles looking distinctly without child.

Miss Kidman's sometimes waxing sometimes waning appearance since her marriage to country music singer Urban has resulted in her being questioned constantly on the subject.

Reports started to surface as far back as June when Miss Kidman, who has two adopted children with her former husband Tom Cruise, was pictured with a bump clearly visible under her tee-shirt as she made preparations to marry Urban in Sydney.

That was not the first time she had faced pregnancy rumours during their romance.

Last year he was also pictured gently patting her stomach at a family get-together.

It had been suggested that Miss Kidman felt desperate to conceive after getting together with Urban while Cruise was busily - and much more publicly - touring his new romance with actress Katie Holmes round the world like some kind of circus.

Cruel detractors have drawn comparisons with Cruise and Holmes's relationship, which brought them a baby, named Suri, a showbusiness wedding and bags of sometimes dubious publicity.

Since Kidman married Urban in the summer, the reports have focussed less of their happiness, but more on Urban's spell in rehab for alcohol.

Such was her exasperation at the constant speculation about being pregnant, that Miss Kidman eventually broke her silence this month and told the Mail: "No, I am not pregnant.

"One minute I'm being told I'm too thin, the next I'm told I'm fat and it must be because I'm expecting a baby.

"It's very confusing. My mum rang me up and said: "Are you pregnant?", and I said: "No, Mum, you'd be one of the first to know," and we just laughed about it because there's not much else you can do."