The multi-million selling Brit Award-winning musician will take to the stage with the BBC Scottish Symphony Orchestra.
She will also be joined by Gary: Tank Commander star Greg McHugh, Britain's Got Talent winners Collabro and Scottish mezzo-soprano Karen Cargill.
The event takes place at Glasgow Green on 10 September.
The singer, who grew up in St Andrews, said she was looking forward to the "adventure".
She added: "It's such a great honour to perform with the BBC SSO as well as a beautiful musical adventure to re-imagine songs in different ways.
"There's a deep and rich world to be found in recreating songs with orchestral arrangements and everyone, performers and listeners alike, comes away from it with an expanded creative mind."
Singer-songwriter KT Tunstall is set to play at the Proms in the Park event in Glasgow next month.