Celebrities who snap back into shape days after giving birth are often the envy of mothers who wonder just how they managed to do it.
Now a fertility doctor has shed a controversial new light on the subject by suggesting they may not have been pregnant in the first place.
Los Angeles-based Dr Vicken Sahakian, who works at the Pacific Fertility Center, said an increasing number of rich and famous celebrities are coming to him asking to have their babies via a surrogate in order to preserve their own figures.
Known as 'social surrogacy', the practice involves perfectly healthy women choosing to pay another to carry and give birth to their child to spare themselves the ordeal, and to avoid having to take a career break if their work depends on them having a flawless look.
'Typically these are women who prefer not to get pregnant and not to go through the process of pregnancy for many different reasons. For instance if you are a model or an actress and your income is based on performing and how you look and pregnancy will ruin that for year, if not more,' Dr Sahakian told presenter Jodie Marsh for her latest TLC documentary Making Babies.
Dr Sahakian, who has performed over 6,000 IVF procedures and is responsible for the birth of more than 3,000 babies over the world, said he has had a number of 'well-known' clients over the years who have opted for a social surrogacy.
He refused to give any names but said some have even faked their own pregnancies whilst secretly using a surrogate.