Liza Minnelli has been forced to cancel a number of concerts over the summer on her doctors' orders. The 68-year-old is suffering from an undisclosed illness and has been told not to perform or travel. 

Liza Minnelli
Liza Minnelli at the Oscars.

Minnelli, who is the daughter of the late actress Judy Garland, has been suffering from ill health of late. She has recently undergone two hip replacements. However, the illness which has caused her to cancel her upcoming appearances is yet to be revealed. 

The statement on her website explained why Minnelli would not be able to appear during July at any of her scheduled concerts. According to the statement, Minnelli's doctors "have advised her not to perform or travel for long period of time because of a medical condition." She is "devastated not to be able to perform" but promises fans she "will see them soon." The statement continued by promising fans and ticket holders the dates would be rescheduled for an "appropriate time". 

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Liza Minnelli
Liza Minnelli performing at the Royal Albert Hall last year.

One of Minnelli's concerts was due to be held at the Royal Albert Hall on July 2nd. Fortunately for those with tickets to the show, the Royal Albert Hall has promised refunds if the tickets were bought through their website. A note underneath Minnelli's performance date on the Royal Albert Hall website reads "Unfortunately this concert has been cancelled due to illness," and "We will be contacting those who have purchased tickets through the Royal Albert Hall to arrange full refunds."

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Liza Minnelli
Minnelli's illness remains undisclosed.