Actress Kristen Bell.

Kristen Bell has compared baby Lincoln to “pre-sobriety” Dax Shepard.

The former 'Veronica Mars' star - who is engaged to the 38-year-old actor - gave birth to their first child on Thursday and joked their daughter is following in her father's footsteps as she “poops her pants” and avoids “paying rent”.

She wrote on Twitter: “My new roomate poops her pants and doesn't pay rent...basically Dax Shepard pre-sobriety. Welcome baby Lincoln xo.”

The couple broke the news on the social networking site when Dax also joked as he made the announcement to his followers.

He revealed: “Lincoln Bell Shepard is here. She has mom's beauty and dad's obsession with breasts. Hooray!”

Their sense of humour was present throughout Kristen's pregnancy, with the 32-year-old actress saying earlier in the year she wanted to be “hit in the face with a baseball bat” during birth.

She said: “I feel like, when I arrive at the hospital, I want a glass of whiskey, I want the epidural in my back and I want to get hit in the face with a baseball bat.

“Wake me up when it's over because I've seen the videos -- and it looks terrifying.” - BANG Showbiz