The 'Beyond The Green' event takes place during the United Nations’ climate change conference in the Scottish city in November.
Also confirmed for next year's event are Wolf Alice, Beabadoobee, Fontaines D.C., Sigrid, Jimmy Eat World and The Snuts.
With most COVID-19 restrictions set to end in Scotland, the event featuring The Chemical Brothers, will proceed as planned.
Sharleen Spiteri and company will play at St Luke's in their native Glasgow, Scotland, on August 5.
The Glasgow event is scheduled to take place July 30, July 31 and August 1, 2021 respectively at the Scottish city's Rouken Glen Park.
The alternative rock band from Glasgow co-founded by Johnny McElhone and Sharleen Spiteri have established a career that's included countless hit singles.
Formerly of pop sensations Liberty X, Simm replaces Wet Wet Wet's original vocalist Marti Pellow.
To celebrate the 30th anniversary of the debut album, 'Popped In Souled Out' Wet Wet Wet is releasing a 5 disc super deluxe remastered edition of the album.
Louis Armstrong visited Great Britain for the first time in 1932…it was quite a visit