During her warm up on the Honda Stage, Demi Lovato burst onto the stage, beginning a rendition of her song Heart Attack. The song first appeared as the opening track on her most recent album, 'Demi'.
Many ticket-holders couldn't get into the O2 Arena show on Tuesday night (September 19th) because they didn't bring photo ID to match their booking.
An album re-release, a new song and a documentary mark the singer's legacy this year.
The actor plays the titular hero in the forthcoming adaptation.