Credit: Tullio M. Puglia/Getty Images Photo: Olivia Newton-John

Olivia Newton-John previously battled breast cancer, and now she's helping her older sister, Rona, through her battle with brain cancer.

Rona — who was married to Olivia's Grease star Jeff Conaway from 1980 to 1985 — was recently diagnosed, and Olivia told Entertainment Tonight she would be postponing her Las Vegas concert series to take care of her sister. "I have decided to postpone my forthcoming Las Vegas residency to spend time with her and our family," Olivia said (via Us Weekly). "As a cancer 'thriver' myself, as many people are, I am very aware of the importance of love, support and family during this journey she is about to begin."

Olivia was scheduled to perform at the Flamingo Casino during Donny and Marie Osmond's break. She will reschedule the dates at a later time.

We wish Rona the best of luck in her fight — and good on ya, Olivia, for having your priorities straight!

Source: Us Weekly