This will be their sixth attendance at the annual event and the Princess's first since her recovery from cancer.
The star-studded line-up includes a performance by the cast of Paddington The Musical, pop star Jessie J, Grammy winner Laufey, the band Madness, and actor Sir Stephen Fry.
Comedian Jason Manford will host the show, which also features a performance from the Live Aid musical and a medley celebrating the 40th anniversary of Les Misérables.
The event serves as the annual fundraiser for the Royal Variety Charity, which supports entertainment industry professionals and launched a dedicated mental health initiative in 2024.