The Scottish stars join Lionel Richie, who headlines on Saturday, 20 June, and David Gray, who celebrates the 20th anniversary of his seminal album 'White Ladder'.
Tears For Fears, Lauryn Hill, Gladys Knight and Kylie Minogue headlined the 2019 series at the legendary venue.
Originally released on 7 March 1983, the album peaked at No. 1 on the UK Albums Chart in its second week of release.
The best music festivals of 2019 cover everything from rootin’ tootin’ country music to ear-blasting rock and all-nighters in the heart of Europe.
Knight joins this year's other headline acts Lauryn Hill, Tears For Fears and Kylie Minogue.
The '80s pop icons will be supported by post-punk five-piece White Lies and chart-topping synth-pop outfit Scritti Politti.