Conor McGregor, girlfriend welcome son Conor Jr.

Conor McGregor is a father.

The UFC lightweight champion and his longtime girlfriend, Dee Devlin, welcomed their first child Friday night in Dublin. McGregor shared a photo of his son, Conor Jack McGregor, on Instagram Sunday morning to announce his arrival.

"Dee and Junior are doing great everyone!" McGregor captioned the photo. "Thank you for all the kind words, I am one proud and blessed Daddy."

McGregor's son is already a social media sensation, as the newborn had acquired more than 40,000 followers on Instagram as of Sunday morning after his parents created a verified account for him.

"There's great news for the McGregors and the Devlins," Tony McGregor, baby Conor's grandfather, told the Irish Mirror Saturday. "Baby Conor Jack McGregor was delivered last night at 8 p.m. in the Coombe Hospital. He came in at 8 pounds, 14 ounces. The whole family are absolutely delighted."

McGregor announced he and Devlin were expecting their first child together after he defeated Eddie Alvarez by knockout at UFC 205 in November.