Christina Aguilera reportedly has to wait at least six weeks until she can start working out after the birth of her daughter.
The American singer gave birth to daughter Summer Rain less than two weeks ago, with fiancé Matthew Rutler.
She already has son Max with ex-husband Jordan Bratman, and sources say she's eager to get back into shape as soon as possible.
"She thinks there's no time to lose," an insider revealed to the American edition of OK! magazine. "Her target is to have her pre-pregnancy body back by her December 18 birthday."
The source adds the Beautiful singer is planning to shed at least 40lbs over a four month period. She'll reportedly achieve this with daily workouts and a low calorie diet, but will have to hold off with some of her plans to give her time to recover from her recent C-section.
After six weeks 33-year-old Christina will apparently begin her 90-minute daily exercise regime, and it's thought she is already on a 1,800 calories protein and veggie based diet.
As well as wanting to get back into shape there could be another reason she's so determined to look good - a possible Playboy shoot next year.
"Stripping down is totally her style," the insider revealed.
Posing naked is no new thing for the star. She recently shot a feature for V magazine minus her clothes for their August issue, proudly showing off her baby bump.
"As a woman, I'm proud to embrace my body through all stages of life, staying fearless and confident in surrendering to the unknowns the future has in store," Christina explained to the publication at the time.
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