The event will take place on December 9 at the London Palladium and it will be shown on TV on BBC1 in the UK on December 16 at 8pm.
Kylie will be singing her new track Better Than Today and Susan will perform her new single Perfect Day, a cover of the Lou Reed classic.
Adele, Jamie Cullum, Ray Davies and Paloma Faith have also now been confirmed for the show and comedians Lee Mack and Michael McIntyre will also take to the stage.
Acts that were previously announced include Take That, Cheryl Cole, N-Dubz, Spelbound and Jack Whitehall.