Conor McGregor and his fiancée Dee Devlin are also parents to son Conor Jack Jr., 4, and daughter Croia, 2

Conor McGregor is now a father of three!

The mixed martial arts fighter, 32, and his fiancée Dee Devlin welcomed their third baby, son Rían, the athlete announced on Instagram Monday. The couple is also parents to son Conor Jack Jr., 4, and daughter Croia, 2.

The dad of three shared the news with a sweet photo on Instagram of him cradling his new baby boy.

Conor McGregor
Credit: Conor McGregor/Instagram

"The McGregor Clan is now a family of 5 ❤️ Healthy baby boy delivered! Baby and Mammy Wonder Woman are doing great!" McGregor wrote alongside the cheerful photo. "God I thank you for everything you give to me and my family in this world 🙏 My new born son, Rían McGregor ❤️."

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.

McGregor announced his engagement to longtime girlfriend Devlin in August, sharing a sweet selfie of the couple on Instagram and calling her his "future wife." McGregor and Devlin have been together since 2008, and according to Page Six, Devlin grew up down the road from McGregor's hometown in Ireland and has been by his side since he first started his UFC career.

"Every day since I started in this game, she's supported me," he told VIP Magazine back 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."

McGregor added at the time, "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."

Conor McGregor and Dee Devlin
Credit: Dee Devlin/Instagram

In the same interview, Devlin said, "I really admired his dedication to that, too," adding, "He's very funny. He always keeps me entertained and makes me laugh."

On Christmas Day, McGregor announced on Instagram that he and Devlin were expecting their third child. The star shared a photo of his family dressed in matching Christmas pajamas with their son holding up an ultrasound image.

"Happy Christmas everyone, from my family to yours ❤️. So much to look forward to in 2021 👶," McGregor captioned the photo. Devlin, also reposted the photo to her Instagram page, writing "Merry Christmas! ❤️."