With Ireland topping the table for the most Eurovision wins - and Sweden catching up fast. the singer hopes to widen the gap with a record eighth win for RTÉ.
He called it an 'absolute honour' to perform the song he has co-written with Mark Caplice and Laura Elizabeth Hughes.
Here's what RTÉ had to say
According to a statement from Irish state broadcaster, "last August, the national broadcaster held a Eurovision Song Contest Forum and invited key industry professionals, songwriters and performers to come to RTÉ to gain a deeper insight into the present day contest from international Eurovision experts and key RTÉ decision makers.
"The forum created debate and fostered new ideas as to the way RTÉ might approach the song contest this year. Over 300 songs were submitted to RTÉ for consideration before the November deadline. The song was chosen after being selected by a panel of music industry professionals who listened to and judged the shortlisted final entries.
'Together' was purposefully written for the Eurovision Song Contest by writers working in The Nucleus, a new Irish songwriting team and hub, founded by Hamlet Sweeney, that brings the international model of collaborative songwriting to Ireland."