To celebrate their last North American Circus tour performance and punk the singer, Britney Spears' backup dancers took the ringleader's advice and ... got naked!

Well, sorta. As a prank, they stripped down into pink briefs as she performed her hits "Boys" and "If U Seek Amy." Their briefs said "True Brit" on the waistband ...

Britney Spears and her half-naked boy toys rock the house.

Good to see that the gang has a sense of humor and keeps the mood light on stage. We can't wait to see high-maintanence tour continue in Europe.

Click to enlarge more shots of Britney performing in Montreal, Quebec ...

[Photo Credits: BritneySpears.com]