Olivia Newton John performs on stage during the Olivia Newton-John fundraising gala event at the State Theatre on September 30, 2009 in Sydney, Australia.

Olivia Newton John performs on stage during the Olivia Newton-John fundraising gala event at the State Theatre on September 30, 2009 in Sydney, Australia.  

Sergio Dionisio/Getty Images

Olivia Newton-John has postponed her May concerts due to what her management is calling "a bad issue" with her sciatica. 

The announcement was made Tuesday (May 9) on the singer and Grease star's Facebook page. 

"Once the dates are rescheduled we will post the new dates ASAP. Apologies for any inconvenience," the message read. 

Newton-John had eight Midwest dates scheduled between May 10–20. She has more concerts planned for June and later in the year.