Their baby girl was born late Saturday in London, People.com reported.
"They are absolutely delighted they have a daughter," the actress' representative, Karon Maskill, told the magazine. "It's a lovely Christmas present for the family."
Bonham Carter and Burton, who also have a 4-year-old son, were each nominated for Golden Globes for their work on "Sweeney Todd" last week. Bonham Carter was in the doctor's office when she heard the news.
"We were talking about inducing and Tim got a call from his assistant," Bonham Carter told People before the baby was born. "I do look like a globe, so it's kind of funny. I am very round."
Bonham Carter and Burton have also previously collaborated on the films "Planet of the Apes," "Big Fish," "Charlie and the Chocolate Factory" and "Corpse Bride."