He sang the Evanescence hit 'Wake Me Up' which was originally sang by a female singer and is extremely high in places.
Rixon was blissfully unaware of the judges grimaces as he tried to hit some of the higher notes in the song.
None of the judges turned around to choose Rixon for their team, but when they did turn around at the end, they were all shocked by what they saw.
Dolores O'Riordan from The Cranberries laughed and said: "You're a dude, oh my God, I totally.....that's pretty phenomenal. My brain is destroyed altogether, I wasn't expecting that at all".
Bressie made a joke about dogs being the only ones able to hear the high notes while Kian Egan praised him on giving them a go.
He was advised to take singing seriously and to come back and try again next year.