The short message, which reads: “Dublin, December 14th,” was posted on his official Twitter account, raising speculation that he intends to return to the octagon in his home town later this year.
CNN has contacted McGregor’s agent for comment.
The 31-year-old last fought in October 2018, when he was beaten by Russian mixed martial artist Khabib Nurmagomedov. The Irishman announced his retirement in March.
Rumors have been swirling about a possible comeback since McGregor told ESPN in August that he “would look for” a fight for the “end of the year.”
McGregor has had a turbulent time away from the sport, hitting the headlines for allegedly punching a man in the head in April. This followed his arrest the previous month on allegations that he smashed a fan’s phone in Miami. Florida prosecutors subsequently dropped the charges.