Live from the B&W Hallerne, Copenhagen, Denmark, artists from 26 countries will take to the stage hoping to be crowned winner in the 59th annual contest. Among them, hopefully, will be Ireland's entry Heartbeat, sung by Kasey Smith and performed with Can-Linn.
Viewers in Ireland can vote for any of the other 25 finalists tonight.
The contest takes place in Denmark, following Emmelie de Forest's win in the 2013 contest with the song Only Teardrops. This will be the third time that Denmark will host the contest, the last time being in 2001.
Eurovision this year is hosted by Pilou Asbæk, best known to viewers as Kasper Juul in Danish political drama series Borgen; musician Nikolaj Koppel and former X-Factor Denmark host Lise Rønne.
RTÉ Television commentary: Marty Whelan