The pop star, who performed in the Legend's slot at this year's Glastonbury festival in June and recently headlined Brighton Pride, will perform before the celebrities are partnered with their professional dance partners.
Before learning who they will be dancing with in the competition, the 15 celebrities – from Olympic gold winner James Cracknell to EastEnders star Emma Barton – will take part in a group routine.
Also on the show, new judge Motsi Mabuse will make her debut alongside Craig Revel-Horwood, Shirley Ballas and Bruno Tonioli. She replaces ballerina Darcey Bussell, who stepped down from the judging panel after seven years.
Last year's series saw broadcaster Stacey Dooley lift the Glitterball trophy with professional partner Kevin Clifton.
Strictly Come Dancing is expected to launch on BBC One on 7 September.