Britney Spears injected a little drama in her otherwise surprisingly drama-free "Circus" tour Wednesday night when decided the show must not go on.

Spears was 15 minutes into her show at Vancouver's GM Place when she abruptly left the stage after three songs in, according to People.  Her departure was blamed on cigarette smoke-not hers, although the singer has been photographed more than once with a pack of cigarettes in her hand- but on smoke in the arena, according to an announcement made over the loudspeakers.

At first fans assumed Spears had left the stage for a costume change, according to the Vancouver Sun, but when she didn't return after 10 minutes, they became concerned. "It's become uncomfortable and unsafe for the performers, including Ms. Spears," announced a female voice, eliciting big boos from the crowd. "The show will resume as soon as the air around the stage is clear," recounts the Sun.
Roughly 40 minutes later, Spears resumed her show and finished without incident.

Her website posted an apology on her website  saying , "crew members above the stage became ill due to a ventilation issue."

The tour is expected to resume tonight as planned in Tacoma, Wash.