JOHN Farnham has revealed Olivia Newton-John has told him she is confident of beating breast cancer for a second time.

Newton-John announced today what she believed was sciatica was sadly breast cancer that metastasised to the sacrum.

The 68-year-old had been experiencing severe back pain during her current US tour, which is now on hold while she undergoes a mix of photon radiation therapy and natural wellness therapies.

Farnham, a long time friend and musical collaborator, had been in touch with Newton-John after she shared her health battle with him.

“I’ve spoken to Olivia in the last few days, and, as always she is very positive,” Farnham said.

“She told me she is feeling good and confident of a total healing. The love and support from family and friends as well as people in general is enormous comfort to her.

“I’ve also spoken to Doctor Cebon at Olivia’s Wellness Center, and he tells me that her positivity is a great asset to her and if anyone can beat this she can.”

The singer’s management said the singer is “confident she will be back later in the year, better than ever” to finish her concerts.

RELATED: Olivia Newton-John can’t catch a break

Tina Arena joined the legion of people shocked by the news.

“Olivia has been a dear, dear friend for a long time,” Arena said this morning.

“She is someone I have the absolute utmost respect for. She’s a human being who’s given so much to the fibre of this country and also to the world. Knowing the kind of woman she is, she turns things around and she is capable of turning this around too. She is a fighter.

“Australia will rally behind Olivia, the world will rally behind her because she’s loved and that love will make her move forward. That’s what I believe.”

Arena said Australia could show their support by continuing to donate to the Olivia Newton-John Cancer and Wellness Centre in Melbourne, which launched in 2012 after many years of fundraising and lobbying.

“Olivia gives so much back,” Arena said.

“She’s continually working on her Cancer and Wellness Centre, raising money for the continual expansion of it. It is an extraordinary foundation that she set up a long time ago. Cancer is very prolific in Australia, we are very progressive from a medical perspective and the public need to support her centre because cancer affects everybody.”

Delta Goodrem, who spent the summer playing Olivia Newton-John in an upcoming Channel 7 miniseries, called the musical icon her hero.

Goodrem posted today she was “Sending my deepest love and support to my hero, friend and mentor Olivia as she starts treatment. If there is one person that embodies hope and healing it’s Olivia. She is one of the world’s kindest and most giving humans and I send you all my love and well wishes. Love you so much. All my heart Delta xx.”

The pair are long-time friends, becoming particularly close after Goodrem’s own cancer battle.

Goodrem recorded the song Right Here With You, donating proceeds to Newton-John’s Wellness Centre, and has also attended the centre in Melbourne.

Channel 7 have been approached about any potential changes to the screening date of their miniseries, which was expected to air either later this year or early next year.

Molly Meldrum, whose friendship with Newton-John stretches back to the ‘60s, said the singer is rightly considered one of the music world’s most liked performers.

“Olivia is one of the nicest people in the industry, and one of the most talented,” Meldrum said.

“She’s also very brave and very strong. She doesn’t like too much fuss being made about her, but I’m sure she’ll get through this just as she did before.

“Olivia is such a great inspiration to people with the way she survived cancer, and I know she was a great source of inspiration for Delta when she had her own battle with cancer, she gave Delta a lot of strength.”

Meldrum is impressed with how much of her time Newton-John gives to her Wellness Centre.

“She works tirelessly for that centre,” he said.

“In a way she’s still like the same girl I met way back, she’s still very down to earth, very honest and very, very strong. I know she’ll get through this.”

Newton-John has enjoyed a career resurgence in Australia in the last two years.

Her joint Two Strong Hearts tour with John Farnham in 2015 spawned a No. 1 live album, her first chart topper since the 1998 Main Event live album, also with Farnham as well as Anthony Warlow.

Last December she scored her second chart topper in two years when another collaboration with Farnham, festive album Friends For Christmas, reached No.1.

Last year she released an album called Liv On, full of positive ‘healing’ songs “for anyone facing a time of challenge in their life, whether it is grieving a loss or on the journey to health and recovery.”

After beating cancer first time around, Newton-John has released several “new age” albums.

2005’s Stronger Than Before was filled with songs specifically for women touched by cancer, another album, Grace and Gratitude, had all profits given to cancer charities.

Newton-John makes frequent trips back to Australia to promote her Cancer and Wellness Centre.

“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,” Newton-John said in the statement announcing her diagnosis.

The singer has been in discussions for events to mark the 40th anniversary Grease next year.

In 2012, the star created the Olivia Newton-John Wellness and Research Centre in Australia.

“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 in the statement.

Newton-John will undergo “a short course of photon radiation therapy” in addition to natural wellness remedies.

The star said she’d be “back later in the year, better than ever.”

Newton-John’s daughter Chloe Lattanzi took to Instagram on May 9 after her superstar mum initially postponed tour dates due to back pain, asking fans for “healing prayers”.

“I love u mama. Miss U so much. Will all of u send healing prayers for my mamas back please [sic].”

She added: “I believe in the power of positive thinking and energy. Love u all [sic].”

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

Fans were instructed to check her website for rescheduled tour dates.

A statement from the Olivia Newton-John Cancer Wellness & Research Centre was also issued today, saying: “The staff, students and Board of the Olivia Newton-John Cancer Wellness & Research Centre, a partnership between Austin Health and the Olivia Newton-John Cancer Research Institute, send Olivia their well wishes as she undergoes treatment following the relapse of her breast cancer, and are sending her positive thoughts for a speedy recovery.”

“Olivia, as the founding champion of the Olivia Newton-John Cancer Wellness & Research Centre (ONJ Centre), has long been committed to supporting wellness programs and improving the treatment and care of people with cancer through innovative research.”

Professor Jonathan Cebon, the medical director of the Olivia Newton-John Cancer Research Institute and of Cancer Services at Austin Health, said he was saddened to hear Olivia’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.”

Other stars have left their tributes on social media:

Sending @olivianj and her family all our love, support and healing. Olivia embodies so many incredible inspiring qualities as an artist... pic.twitter.com/hVit8djgt6 — Human Nature (@HumanNatureLive) May 30, 2017

and even more so as one of the most generous and amazing humans & philanthropists. All our love & light Andrew, Toby, Mike & Phil x — Human Nature (@HumanNatureLive) May 30, 2017

Sending so much love to @olivianj with the news of her health this morning. She is a fighter and has a nation behind her 🙏🏻 — David Campbell (@DavidCampbell73) May 30, 2017

Our love and prayers for a speedy and full recovery go out to Olivia Newton-John. #oliviafullrecovery — Joe Hockey (@JoeHockey) May 30, 2017

If you would like to send Olivia a message of support please email enquiries@ONJCRI.org.au. If you would like to make a difference you can donate to the ONJ Centre by visiting http://www.onjcancercentre.org/donate or phoning +61 3 9496 9128.