Former two-weight UFC champion Conor McGregor says he has "retired from the sport formally known as 'Mixed Martial Art'".
The Irishman announced his decision on social media on Tuesday.
McGregor, 30, made his MMA debut in 2007, with the former trainee plumber quickly establishing himself as one of the sport's leading fighters.
His last fight ended in defeat, when he was beaten by Khabib Nurmagomedov in October 2018 - the Russian winning the lightweight contest by a fourth-round submission.
It was his first fight in the octagon in two years and the defeat was marred by a post-fight brawl which led to both fighters being fined and suspended.
This is not the first time that McGregor has announced his retirement from the sport.
In April 2016, McGregor tweeted: "I have decided to retire young. Thanks for the cheese," and was then not included on the UFC 200 card.
But he quickly issued a retraction outlining that he had instead fallen out with the sport's bosses over promotional work.