The trio were revealed via a digital treasure hunt in which festival fans followed clues on Google Maps to discover the identity of the headliners, with the festival confirming their identities at 5pm.
2020 will see the return of Lewis Capaldi, who stepped in to replace Snow Patrol at 2019's festival. The pair will both perform on Sunday 12th July.
Capaldi has performed at TRNSMT every year since its inception, and will be bringing string of hits, including 'Someone You Loved', 'Hold Me While You Wait' and 'Bruises' to Glasgow Green for what will be his first major UK festival headline set.
Meanwhile britpop icon Liam Gallagher will headline TRNSMT on the Saturday night, bringing a mix of his solo material and Oasis classics to the festival, while Friday night welcomes Manchester band Courteeners and their swinging indie hooks and singalong sermons.