US pop superstar Britney Spears is doing a lot of research as she wants to make her upcoming performance at London's O2 arena memorable.
According to thesun.co.uk, Spears spent more than a week in London and has been reviewing video footage of shows there.
She has people who are reporting back to her on the shows by Girls Aloud and Pussycat Dolls.
A source who was present for Spears' rehearsals for the tour said: "Britney knows these shows are absolutely crucial. She hasn't played in the UK for five years so there is a lot riding on them."