Baby boy Axl Jack Duhamel weighed in at 7 lbs., 10 oz., their rep confirmed.
Fergie, 38, and Duhamel, 40, have been together since September 2004, and were married in January 2009.
The couple announced the pregnancy in February on social media (complete with the hashtag, "mylovelybabybump," naturally), and let it slip they were expecting a boy in July.
Congratulations to the new parents!
Celebrity Breakups and divorces of 2014 [PHOTOS]