Olivia Newton-John is delaying a forthcoming tour after learning she's facing a second cancer battle 25 years after her first diagnosis.

Newton-John, who was scheduled to play a string of concerts across the United States and Canada, said in a statement uploaded to Facebook that she learned she had cancer after wrongfully assuming pain in her back was an onset of sciatica. Now, it has metastasized to her sacrum, but the singer says she's still confident she'll overcome the disease.

"I decided on my direction of therapies after consultation with my doctors and natural therapists and the medical team at my Olivia Newton-John Cancer Wellness and Research Centre in Melbourne, Australia,” she wrote.

Now, she'll undergo "short course of photon radiation therapy" and hopes to be back on the road and in front of her fans by the year's end.

“She plans to be touring in August. They’re all very positive,” a source close to Newton-John told People.

Newton-John previously battled cancer 25 years ago in 1992. Her latest album LIV ON addresses overcoming cancer and living with the trauma of the illness. She has since become and advocate and spokesman for several breast cancer awareness charities and organizations and has endorsed Liv-Kit, a tool with which women can self-examine their breasts for abnormalities.

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