Latvia participated in the Eurovision Song Contest 2017 with the song "Line" written by Agnese Rakovska, Kristaps Ērglis and Kristians Rakovskis. The song was performed by the group Triana Park. The Latvian broadcaster Latvijas Televīzija (LTV) organized the national final Supernova 2017 in order to select the Latvian entry for the 2017 contest in Kyiv, Ukraine. 22 songs were selected to compete in the national final, which consisted of four shows: two heats, one semi-final and a final. In the heats and the semi-final, four entries were selected to advance from each show: two entries selected based on a public televote and two entries selected by a four-member jury panel. Four songs ultimately qualified to compete in the final on 26 February 2017 where a public vote exclusively selected "Line" performed by Triana Park as the winner.

The United Kingdom participated in the Eurovision Song Contest 2017 with the song "Never Give Up on You" written by Daniel Salcedo, Emmelie de Forest and Lawrie Martin. The song was performed by Lucie Jones. Songwriter Emmelie de Forest represented Denmark in the Eurovision Song Contest 2013 with the song "Only Teardrops" where she won the competition. The British entry for the 2017 contest in Kyiv, Ukraine was selected via the national final Eurovision: You Decide, organised by the British broadcaster BBC. Six acts competed in the national final and the winner was selected through the combination of a public vote and the votes of an eight-member professional jury.