Olivia Newton-John has revealed she is battling cancer for the second time, 25 years after she was first diagnosed. 

The Australian singer and actor was forced to postpone her US and Canadian tour dates next month after discovering back pain was actually breast cancer that has metastasised to her lower back.

That same back pain had earlier caused her to postpone the first half of her tour, before the cancer was discovered.

In a statement on her Facebook page early on Wednesday, Newton-John said she was confident after a short course of photon radiation therapy she would “be back later in the year, better than ever”.

“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 said.

Newton-John’s longtime friend Richard Wilkins lost his composure when sharing the news on the Today show on Wednesday.

“Sad news this morning and spare a thought for the gorgeous Olivia Newton-John, please” he said.

“The back pain that has been causing her issues recently, we thought it was sciatica, has turned out to be breast cancer.”

Wilkins was forced to pause as he became emotional.

“Sorry,” he said. “We send her all our love. She’s a wonderful person. It is so sad.”

Sending all our love to @Olivianj as she postpones her immediate concert dates to undergo a short course of radiation therapy. #9Today pic.twitter.com/dorY68wGUt

— The Today Show (@TheTodayShow) May 30, 2017

Professor Jonathan Cebon, the medical director of the Research Centre, said he was saddened to hear Newton-John’s cancer had returned.

“Late relapses from breast cancer can occur, especially for women with ‘hormone receptor-positive’ breast cancer,” Professor Cebon said.

“These relapses can occur sometimes even decades after initial treatment for early breast cancer.

“This unpredictability of breast cancer, and its ability to return after many years, is an area of active research at the institute through our Translational Breast Cancer Program.”

Newton-John opened the Olivia Newton-John Cancer Wellness and Research Centre in The Austin Hospital in 2014.

The British-born Australian star first battled breast cancer 25 years ago and has since used her own experience to promote awareness about the disease.