Cameron Diaz says giving birth in her new movie was "really fun".

The actress stars as a pregnant woman in upcoming film What to Expect When You're Expecting and enjoyed filming her birthing scene.

The comedy tells the story of five couples as they prepare to become parents.

Starring alongside Jennifer Lopez, Elizabeth Banks, Brooklyn Decker and Anna Kendrick, the blonde beauty said that each character's delivery sequence was fascinating.

"That was fun - really fun," she told E! Online. "In this movie, everybody's delivery scene is amazing."

However, Cameron admitted that she is aware playing an expecting mother is nothing like the real thing.

The 39-year-old added that she still hasn't developed any feelings of broodiness.

Cameron is said to be dating rapper P. Diddy but insisted she isn't feeling particularly maternal.

"I think the only thing that's like being pregnant with that [fake] pregnancy belly was it was really hard to sit down," she laughed. "I'm not worried about that [starting a family]. I don't think that [fake] belly is what I should base wanting to be a mama on."