Posh and pecs: After three children, Victoria Beckham is hitting the gym

She is famed for keeping her whippet-thin body in shape by nibbling on edamame beans washed down with spinach shakes.

But now Victoria Beckham – who once proclaimed that she ‘hates working out’ – has signed up for a programme of exercise classes in the hope they will boost her pelvic muscles.

Posh has joined Hollywood’s ultra-exclusive The Sports Club LA, a private members’ gym that costs £1,500 a year – plus a £250 monthly fee.

An insider at the gym told The Mail on Sunday that the mother of three, who turned 35 on Friday, has enrolled in private Pilates classes, which promise to strengthen and tone core stomach and back muscles – and boost pelvic strength.

The source said: ‘Victoria has signed up for private Pilates classes. She comes into the gym at least three times a week and her husband David joins her for Pilates when he’s in town.

‘Pilates is specifically aimed at building up the core muscles and is particularly good for women who want to strengthen their body.