Britney said she met her at the VMAs (Adele didn't attend the 2008 VMAs,) so I assume this was backstage this year right before they started getting ready for the show, since both of them didn't have any make-up on. It looks like it was shot during the "Circus"/"19" eras though.
Adele has met Britney before. She said in an interview she was gonna see the Circus show and meet the Queen of Pop.
