Britney Spears dramatically stormed off stage for an hour on Wednesday after complaining the air in the venue had become too smoky.

Fans were stunned when the star halted her show in Vancouver, Canada after just three songs, leaving the audience waiting for more than 20 minutes for an explanation.

An announcement was then made, reportedly ordering the audience to stop smoking marijuana and cigarettes in the arena as it was "unsafe" for Spears to perform.

After a further 40 minutes, Spears finally re-emerged - but a concertgoer tells blogger Perez Hilton the star looked upset by the interruption, adding: "She did not look into it at all!"

When the show ended, Spears took a moment to warn against smoking, telling the crowd: "Thanks Vancouver. You were wonderful. Drive safe. Don't smoke weed!"

A representative for the star has since explained that the glitch was caused by poor air circulation.

And concert organisers at Orca Bay Sports and Entertainment denied marijuana smoke was to blame, insisting audience members were puffing cigarettes.

A statement from Spears' camp reads: "We want to apologise to all the fans who attended our Vancouver show tonight for the brief pause in Britney's set. Crew members above the stage became ill due to a ventilation issue."

(by Daniel Melia)