Conor McGregor and fiancée Dee Devlin welcome baby boy: 'Family of 5'

Conor McGregor is the father to a new baby boy!

The UFC fighter, 32, welcomed his third child, a boy named Rían with fiancée Dee Devlin.

"The McGregor Clan is now a family of 5," McGregor wrote on social media, alongside a photo of him cradling his newborn. "Healthy baby boy delivered!"

McGregor added, "Baby and Mammy Wonder Woman are doing great! God I thank you for everything you give to me and my family in this world."

McGregor and Devlin also share Conor Jr, four, and daughter Croia, two.

The mixed martial arts fighter announced news of his engagement to Devlin in August last year.

"What a birthday, my future wife," he captioned a sweet selfie of them on Instagram.

READ MORE: Conor McGregor announces engagement to his partner of 12 years Dee Devlin

"Every day since I started in this game, she's supported me," he told VIP Magazine in 2013. "She'd drive me to the gym, and she'd listen to all my dreams. I wouldn't be doing this if it wasn't for her."

The couple grew up on the same street in Ireland, and have been inseparable since they started dating in 2008.

He said, "I knew her a bit beforehand, but I think the first time I spoke to her properly was when I saw her in a nightclub. I asked her to come over and we just started chatting. She seemed like a nice girl, and I like good girls."