Janet Jackson has left the Montreal hospital she entered so frantically Monday, she is still mysteriously ill but thankfully recuperating and her tour seems to be somewhat in jeopardy…

Janet Jackson was busy with a sound check Monday evening in Montreal, Canada, preparing for the night’s concert, when she suddenly felt ill and was rushed to a local hospital.

Jackson is currently in the midst of a new tour, the Rock Witchu Tour, in support of her most recent album, “Discipline.”

Fans learned of the night’s disappointment just minutes before LL Cool J, who was opening the show, was due to appear on stage. A representative for the singer said she hoped to reschedule the aborted gig.

Jackson’s camp has been very enigmatic regarding the whole situation. The condition of her illness was not revealed. For instance, it is not known whether she had been in poor health before and this was some kind of a relapse or whether she was just suddenly taken ill.

We are only left to speculate that perhaps her condition is not terribly serious, as she was released from the Royal Victoria Hospital in Montreal after a couple of hours. She does however need some time to recover and two more dates have consequently been postponed.

The 42-year-old singer delayed her Wednesday, Oct. 1 show in Boston and the Thursday, Oct. 2 show in Philadelphia. She will be in Greensboro, N. C. this Saturday, Oct. 4 though.

Jackson has been on the road since Sept. 10, when she kicked off the Rock Witchu Tour in Vancouver, Canada, to rave reviews. This is her first tour in seven years, after the extremely successful All For You Tour of 2001, in support of the homonymous album.

Jackson released “Discipline” via Island Def Jam in February of this year. The album, her tenth studio effort, debuted at No. 1 on the Billboard 200, becoming her sixth album to reach such high standards and thus guaranteeing her an exquisite status.

Multiple Academy Award winner Barbra Streisand holds the most albums to debut at No. 1 on the Billboard 200 – eight. She is followed by the Queen of Pop, Madonna, with seven, and Mariah Carey and Janet Jackson, who tie at six.

Jackson has had health problems before this year, but again, she did not elaborate much at the time. In March, she dropped out of a scheduled “Saturday Night Live” performance because she had the flu.

This time around, it may just be that the rigors of preparing such a grand-scale concert tour, what with prolonged rehearsals, a hectic schedule, the great physical effort and frequent pre-show jitters, have taken a toll on her health.

A source close to Janet Jackson’s boyfriend, Jermaine Dupri, told People magazine that the singer had recently complained of feeling exhausted.