UFC star Conor McGregor is under investigation in Ireland after a woman accused him of sexual assault.

The New York Times reports that the alleged assault occurred in December and he has not been charged as yet but is under investigation.

Yesterday McGregor said on Twitter he had decided to retire “from the sport formally known as “Mixed Martial Art”.

McGregor was arrested and charged with robbery in Miami earlier this month after allegedly stamping on a fan’s mobile phone.