Tamara Ecclestone didn't ''expect'' to breastfeed for four years.

The 34-year-old socialite is still nursing her four-year-old daughter Sophia but she has admitted she never planned for it to go on that long and, although her family are ''100 per cent supportive'' of her decision, they can't resist mocking her.

Speaking to Grazia magazine, Tamara said: ''I didn't expect to breastfeed for as long as I have and I never imagined I'd breastfeed for four years but it's been the best experience I've ever gone through.

''It's a bit of a running joke in the family - but they don't mean it in a bad way. They are 100 per cent supportive. I guess they chuckle to themselves about it.''

Sophia also still sleeps in Tamara and her husband Jay Rutland's bed, but she's adamant it hasn't had any impact on their sex life because they get down to business in other rooms around their sprawling mansion.

She said recently: ''Now he really, really likes it and he comes to bed later than us. I hear him getting into bed and kissing her and I know that he loves having her there. I know that he wouldn't have it any other way. I think it was a little bit of an adjustment at the beginning, but he says that he's happy.''

When asked how they get frisky, Tamara - the daughter of former Formula One Group chief executive Bernie Ecclestone and Serbian model Slavica Ecclestone - replied: ''There are other rooms! There are other places, there are other rooms. That's fine, the bed is for sleeping ... at least in our house.''