Camp icon McDonald will appear along Sinitta as the contestants on this season's Snatch Game, while Olympic diver Daley, comedian Ryan, Strictly Come Dancing judge Motsi Mabuse and acting veteran Richard E Grant are among the extra special guest judges.
Other judges include singer-songwriter Kim Petras, actor Adwoa Aboah and singer Self Esteem - and in the season's choreography challenge, Strictly legends Aljaz Skorjanec and Janette Manrara lead a mentoring session.
"I am the biggest Drag Race fan," said Daley, who is now in training ahead of the Paris 2024 Olympics. "It's the most iconic show on TV with so many one liners that've made it into my daily dialogue.
"It's been a long time coming, and I'm finally going to be a guest judge! After all, Drag Race is the Olympics of drag. But what shall I wear? Red wig and a silver dress? I don't think."
Expert cruiser McDonald added: "Sitting alongside Ru was a dream, each and every one of the queens were spectacular and FABULOUS and showcased talent from right across the globe - May the best drag queen win!"
RuPaul's Drag Race UK vs The World begins Friday, February 9 on BBC Three and iPlayer.
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