Hannigan’s rep announced that the How I Met Your Mother star and her husband, actor Alexis Denisof, welcomed their daughter on March 24, according to People.
The new parents had been keeping the baby’s sex a secret during the pregnancy. The little girl, who was born on her mother’s 35th birthday, is named Satyana Denisof.
"They’re very excited, and mom and baby are doing great," said Hannigan’s rep.
Hannigan and Denisof met on the set of the television series Buffy the Vampire Slayer in 1999.