"Well, it's official. I am a daddy again. And my wife deserves an award for her incredible strength and amazing demeanor. #luckiest-man," Gad tweeted.
The child's name and birthplace were not disclosed.
UsMagazine.com said the couple got married in 2008 and have an older daughter named Ava.
Gad is best known for starring in "The Book of Mormon" on Broadway, as well as lending his voice to Olaf the talking snowman in the animated musical "Frozen."