Olivia Newton-John's showbiz pals have reached out to the star after she revealed her breast cancer has returned.

The 68-year-old actress-and-singer postponed her planned performances next month in the US and Canada after learning the life-threatening disease had spread to her back on Tuesday (30.05.17).

Drag Queen RuPaul, 68, wrote on Twitter: ''Let's all send Olivia healing love energy @olivianj (sic)''

Pop star Sara Bareilles hailed the 'Grease' star ''the bravest'' for opening up about her battle with cancer for the second time.

The 37-year-old singer wrote on the micro-blogging site: ''My heart and prayers are with you @olivianj. You are the bravest and the strongest!! (sic)''

And Dolly Parton's sister Stella, 68, wrote: ''Will be praying you make a speedy recover. Sending lots of love. You are stronger than you know. (sic)''

A source has told PEOPLE magazine that the 'Physical' hitmaker's family have high hopes that she should be back on the road in August.

They said: ''She plans to be touring in August. They're all very positive.''

She has vowed to fight the disease with the help of her own Olivia Newton-John Cancer Wellness and Research Centre based in Melbourne, Australia.

The actress will be helped by natural therapists, though she will have to undergo a ''short'' course of radiation therapy.

On her treatment plan, she said: ''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.''

Olivia has promised she will be back fighting fit and will reschedule her shows soon.

A statement posted on the star's Facebook page read: ''Olivia Newton-John is reluctantly postponing her June U.S. and Canadian concert tour dates. The back pain that initially caused her to postpone the first half of her concert tour, has turned out to be breast cancer that has metastasized to the sacrum.

''In addition to natural wellness therapies, Olivia will complete a short course of photon radiation therapy and is confident she will be back later in the year, better than ever, to celebrate her shows.

There will be no interview requests accepted at this time as Olivia's focus is on her treatment and healing. Ticket buyers for the upcoming concerts should contact venues directly about refunds. Rescheduled concert dates will be posted at OliviaNewton-John.com in the coming weeks. (sic)''

Olivia - who has 31-year-old daughter Chloe with her ex-husband Matt Lattanzi - was previously diagnosed with breast cancer 25 years ago in 1992, and underwent a partial mastectomy.