Jennifer Westfeldt knows what it's like to be "out of sync" with friends.

The 42-year-old is promoting the movie Friends with Kids, which she wrote, directed and starred in.

Jennifer and her long-term partner Jon Hamm don't have children and the movie is about pals who take different paths when it comes to family. Jennifer has hinted it is based on her life experiences.

"It's that notion of being out of sync with your peer group as they embark on this journey, one by one," she told UK magazine Grazia.

In the movie, two friends decide to have a child together as they can't find their perfect partners. Their peers have varying reactions to the plan, with some of them struggling to adapt to parenthood themselves.

"You really feel that distance," Jennifer remarked. "You also watch how their romantic relationship changes, especially in that first year when everybody is exhausted and stressed."