Congrats are in order for Conor McGregor and Dee Devlin -- the UFC superstar popped the question to his longtime GF ... and she said YES!!!
The couple -- who have been together for more than a decade -- made the news official on Saturday ... showing off a MASSIVE engagement ring.
The fighter posted about dropping to one knee before Devlin's 33rd birthday, which is August 9 ... but hints it may have happened around his birthday last month.
"What a birthday, my future wife !" Conor captioned his post on Instagram.