She joined stars of the show for a tour of the BBC studio and took a new throne alongside acid-tongued Craig Revel Horwood behind the judges' desk.
And she even held up a score paddle to give her verdict on the dancers in rehearsals, and to crown her own kings and queens of the dancefloor.
Camilla is a fan of the show and has previously danced with Revel Horwood, who is a patron of the National Osteoporosis Society, of which she is president.
The judge personally invited her to today's right royal knees-up.
The Duchess watched some of the show professionals rehearse their group dance - a foxtrot to Adele's Rolling In The Deep, performed by Brendan Cole, Pasha Kovalev, Natalie Lowe and Katya Virshilas.
And she saw competition favourites Harry Judd and Aliona Vilani rehearse a quickstep for tomorrow's BBC1 programme to Don't Get Me Wrong by The Pretenders.
Anita Dobson and guest partner Brendan - standing in for injured Robin Windsor - danced a cha-cha-cha to Uptown Girl by Billy Joel.
There was a further royal date for Sir Bruce Forsyth when he and co-host Tess Daly were introduced to Camilla, just weeks after he attended Buckingham Palace to receive his knighthood.
The Duchess was also taken behind the scenes, visiting the costume department and learning about the preparations which go into designing outfits for the series, and heading into the gallery to see how the footage is mixed.
Click through our slideshow of all the contestants in this series and vote for who you think should take off the title...