Britney Spears is buying a 15,000 oxygen chamber to protect her voice.

The 'Womanizer' singer - who reportedly lip synchs to her songs during performances on her current world tour - is set to splash out the sum because she is terrified of "bad air" ruining her career.

The move comes after Britney stormed off stage in Vancouver, Canada, because the arena was too smoky last month.

Fans at the 27-year-old's Canadian concert in her 'The Circus starring Britney Spears' tour were told the show was stopped because of people smoking cigarettes and marijuana in the arena, making it "unsafe" for Britney and her performers.

Britney later returned to the stage to continue the show, and at the end of her set she told the audience: "Thanks Vancouver. You were wonderful. Drive safe. Don't smoke weed!" 'The Circus starring Britney Spears' is currently finishing its US leg, and scheduled to kick off in Europe with eight shows at London's O2 arena from June 3.