I know the show was recorded last night but strange that Gleb was seen upstairs with Claudia then turned around to applaud James Morrison and there he was again dancing in a different costume. Or maybe it was recorded much earlier or another day

Non-live shows are recorded in whatever order is convenient for the show, and the producers then splice and slice everything so they end up in the order everyone sees.

Re Gleb being in 2 places at the same time - I don't think the producers care that viewers work out the show isn't live, contrary to what many on this forum think. In fact one could say he was in 3 places at the same time as there wasn't enough time after the pro dance for him to change into his "saturday night" outfit/make-up.

Tha'ts the magic of telly!

They get the guest slots and pro dances recorded first. Guests even on a different day, I believe. Imagine how long it would have taken to put all Annie Lennox's thousands of tea lights out and back again when she performed that time.