The Irish singer was performing in Brussels, Belgium last year (13) when he ventured into the audience during a song, and he was so disturbed by a fan grabbing his genitals that he filed a complaint against him.
He tells Britain's Sun on Sunday, "This guy went right under and properly grabbed by balls. So all I could think of doing was turning round and punching him in the face... I felt that my life was in danger.
"His friends started to come at me, it was a big deal... Luckily, the security got them all back... He started saying he was going to call police so I filed a complaint to say the bloke sexually assaulted me and I just reacted."