"I've been going to the studio lately, and we've been trying out different nannies," she said. "It's hard to leave Sean… I'm so torn right now."

She added that – when her second child, expected next month, is born – she will take them both away with her on future tours. She commented: "I think it will be good to have a sibling there with Sean Preston on tour."

Meanwhile, Britney Spears has vowed to get into shape so that she can go a world tour next year reports postchronicle.

Spears says: "I feel like I've been pregnant for ten years .... I can't wait to get back in shape. I'm so excited to really be able to sweat like I used to."

In other news, a poster showing a naked and pregnant Britney Spears has been banned from Japan's subway, because bosses deem it "too stimulating" for young people reports the Sun Uk.

The picture, from the cover of the August edition of Harper's Bazaar magazine, shows the singer naked, but protecting her modesty by covering her breasts with her arms and crossing her legs at the knee.

An official says: "We thought some of our customers would find it to be overly stimulating."