Footage of this year’s session will be included in a BBC One special, Strictly The Professionals, to be broadcast this Saturday.
It features interviews with former contestants. Jake Wood, the EastEnders actor, said the event was unnerving: “The producers all walk around and you’re not sure what they’re looking at,” he said.
Mollie King, the singer and 2017 semi-finalist, joked that “all of us female contestants danced with all of the pro boys and it was one of the best moments of my life, just being swung from man to man”.
Brian Conley, the comedian, said the professional dancers were more interested in where the celebrities were based than their dancing ability.
He recalled: “Everyone will come up to you and say, ‘Hello, where do you live?’ I thought, why does everyone want to know where I live? And it’s because they know they’ve got to rehearse with you and they don’t want to be too far away from London.”