If so, that means the program (sorry, that should "programme") wasn't just a concert, but included some offbeat material. In this case, it's a sequence, that's hosted by Graham Norton, who gets mentioned around here a bit. The premise here is that they're auditioning a bunch of people to be an Adele impersonator -- and into the group, one of the people (in disguise) is...Adele!
She plays a young woman named 'Jenny' and seems to be having a fun time of it. From other videos online, it seems like a shorter version of this was used in the special, but this is the longer, full sequence that probably otherwise took up too much time from the concert.