The R&B singer and husband Shannon Brown welcomed daughter Laiyah Shannon on Tuesday in Atlanta.
Monica, 32, is already mother to sons Rocko and Romelo Montez from a previous relationship, while Brown, who plays for the Phoenix Suns, also has a son named Shannon Christopher.
Brown posted a photo of himself and their new bundle of joy on Friday. "I thank God for her!!! Joy has been restored in my life!!"
The couple met in June 2010 when Brown appeared in Monica's music video for "Love All Over Me." They wed that November.