Gym bunny Gwyneth Paltrow

Gwyneth Paltrow works out for three hours a day.

The 'Iron Man' star - who has two children with her Coldplay star husband Chris Martin - is totally committed to maintaining her svelte figure, according to her chef friend Mario Batali.

Mario, who stars with Gwyneth in US TV documentary 'Spain... On the Road Again', said: "I think she works out three hours a day - which is one of the keys to success. If we all did that, we'd all look like Gwyneth Paltrow - or at least closer!"

Mario also revealed the 35-year-old actress is blessed with a fast metabolism which means she never gains weight.

He added: "Gwyneth loves to eat and, you know, she never puts on a pound!"

Gwyneth and Mario travel around Spain with Mark Bittman and Spanish actress Claudia Bassols in the documentary.

Mario said: "We had an amazing time - we saw everything! It's very much like a road trip, we just drove into a place, figured out what was going on and tried to get a hold of it."