The pair said "Christmas came early" when House Of Lies actress Kristen gave birth to a healthy baby daughter on Friday (19 December).
Hours after giving birth, Kristen told her Twitter fans the happy news.
She wrote: "The estrogen has now hit critical mass! Good luck, @daxshepard1. And welcome to the world DELTA BELL SHEPARD :)."
Proud daddy and actor Dax, meanwhile, tweeted: "Delta Bell Shepard is here. She doesn't look like either @IMKristenBell or me, but we're gonna keep her anyway. #christmascameearly."
In June, a rep for the couple confirmed they were expecting their second child.
Kristen Bell (@IMKristenBell) December 20, 2014
At the time, the statement said: "The whole family is beyond excited."
Kristen, 34, and husband Dax, 39, are already parents to daughter Lincoln, who was born in March 2013.
Frozen star Kristen and Parenthood actor Dax began dating in 2007 and married last year.
Congrats to Kristen and Dax!
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Celebrities who have welcomes babies in 2014:
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