Bulgaria participated in the Eurovision Song Contest 2018 with the song "Bones" written by Borislav Milanov, Joacim Bo Persson, Trey Campbell and Dag Lundberg. The song was performed by the group Equinox. The Bulgarian broadcaster Bulgarian National Television (BNT) organised the internal selection process BG Song 2018 in order to select the Bulgarian entry for the 2018 contest in Lisbon, Portugal. On 12 March 2018, BNT announced that Equinox had been selected to compete with "Bones", which was presented to the public on the same day.

Equinox was a supergroup consisting of Bulgarian singers Zhana Bergendorff, Georgi Simeonov, and Vladimir Mihaylov, and American singers Johnny Manuel and Trey Campbell. They represented Bulgaria in the Eurovision Song Contest 2018 in Lisbon with the song "Bones", coming 14th with 166 points. The group has been inactive after the contest.