The singer "got suddenly ill during the sound check" before her concert in Montreal and had to be rushed to the hospital, according to People.
A statement was released by her PR firm, W&W Public Relations.
Jackson, 42, is being monitored at a Montreal hospital, and there are plans to reschedule the show.
This isn’t the first canceled stop. Last Friday, she called off her Detroit show due to "production constraints," according to TMZ.
She plans to reschedule that show as well. The Rock Witchu Tour also features LL Cool J, and is slated to continue until Oct. 22.
While promoting her new album, "Discipline," in April, Jackson canceled an appearance on "Saturday Night Live" due to bronchitis, according to boyfriend and producer Jermaine Dupri.
Get better soon, Janet!
That album reportedly needs more promotion.
Photo: Janet Jackson in concert in Toronto. Credit: WireImage