Rona (left) and Olivia Newton-John
05/30/2013 AT 09:25 AM EDT
Olivia Newton-John's beloved older sister, Rona Newton-John, has died after a battle with brain cancer.
"My beautiful sister Rona sadly passed on May 24th in Los Angeles. It was May 25th in Australia – which was our mother Irene's birthday," Olivia, 64, wrote on Facebook.
She adds: "Rona died of a very aggressive brain tumor and mercifully suffered no pain. She was surrounded by the love of her four children – Fiona, Brett, Tottie and Emerson, and her wonderful friends. I will miss her forever – my beautiful, smart, talented, funny, brave sister Rona."
star, who beat breast cancer herself
in the early 1990s, revealed just last month that Rona – her elder by six years, and also an actress – had brain cancer. She had been with Rona to support her in recent weeks, just as Rona had done for her two decades ago.
Olivia requests that in lieu of flowers, the family would appreciate donations to the Olivia Newton-John Cancer and Wellness Centre, where a brain-tumor wellness program
will be started in her name.