Isaac Hanson and Nicole Hanson
Nina Odette is the third child for the couple, who are already parents to Clark Everette, 6, and James Monroe, 5.
"After more than five years of not having a baby in the house, having our first little girl is going to be fun," the musician said. "I know that Everett and Monroe are excited about being big brothers."
Hanson, 33, will soon continue a world tour with his brothers in support of their sixth album Anthem.