Christina Aguilera's slimming breasts

Christina Aguilera says her slimline post-baby figure is down to breastfeeding.

The 'Dirrty' singer - who gave birth to son Max Liron, her first baby with husband Jordan Bratman, two months ago - insists feeding hungry Max is "like a workout in itself".

She told US TV show 'Access Hollywood': "I think they say that when you're breastfeeding, you know, your weight kind of slims down. It's a little easier. It's like a workout within itself. It's very tiring actually and you find yourself snacking more often."

Christina isn't the only celebrity to have reclaimed their pre-pregnancy figure through nursing.

'King Kong' star Naomi Watts - who has an eight-month-old son Alexander with fiancé Liev Schreiber - shaped up by working out, but breastfeeding also helped her shed the excess pounds.

She revealed: "Three weeks before we started filming my new movie 'The International' I decided that I better get into changing my body back again.

"They gave me a trainer and it was very effective and also breastfeeding. That's how you drop weight. Even though you're just eating all the time he is eating too."