Janet Jackson thought to be suffering from 'exhaustion'

Janet Jackson is thought to be suffering from "exhaustion".

The 'Feedback' singer, who was rushed to hospital after being taken ill during a sound check for a concert in Canada, had previously refused to comment on the reason for her illness.

But a close friend of the star's boyfriend Jermaine Dupri claims Janet is just very "tired".

The source told gossip blogger Perez Hilton: "A 42-year-old body can't handle what a 22-year-old body can. I can tell you that she's definitely tired. It was probably exhaustion.

"She is doing back-to-back, three-hour shows, and her body isn't the same as it used to be."

Jackson, 42, has delayed her Wednesday show in Boston and a Thursday performance in Philadelphia until further notice. She will resume her tour Saturday in Greensboro, N.C.

This is the second time this year the star has received hospital treatment. In March, Janet checked into the Los Angeles' Cedar-Sinai Medical Center to be treated for flu symptoms after complaining of "shortness of breath".