Britney Spears Concert ('Circus Tour') @ Bell Centre, Montreal, Canada in 5th May 2009.
This was around the end of the concert, with the crew dressed in Cop uniforms (and sirens on the stage, with red and blue rotating lights like on Police Cars). Reminded me of George Michael, as he uses similar themes in his concert for the song 'Outside'.
See more photos here:
Britney Spears Concert 