Nicole Richie Demonstrates Pregnant Sex at Lamaze Class on The Simple Life  6/12/06

Parents-to-be were in for a shock when they signed up for a Lamaze class and discovered a 'pregnant' Nicole Richie was their sexual positions model.

Socialite Richie had to 'become' a nine-month pregnant woman when she replaced the real thing for an upcoming episode of reality TV series The Simple Life - and the daughter of singer Lionel Richie was committed to her role as a mum-to-be.

On the new season of the show, Richie and co-star Paris Hilton swap places with a handful of wives and spend a week taking over their chores and their lives.

She says, "I went to a Lamaze class with one of the husbands because the wife was nine months pregnant, so I had to be nine months pregnant.

"That day they happened to be teaching us about being able to still have sex and they wanted someone to demonstrate, so obviously I did it.

"I just demonstrated being in different positions with the husband and straddling him; he loved every second of it."

Richie also caused tensions when she took the dad-to-be to a strip club: "I wanted him to loosen up a little bit because he's been with his pregnant wife... so I wanted to let him have a little something.

"He sat there and three girls gave him a lap dance and then I just wanted to call her (wife) just to check up and tell her that we were OK, so I handed him the phone... He hung up on her, so that didn't go over very well."