Olivia Newton-John's sister Rona Newton-John dies of brain cancer

olivia-newton-john-sister-rona-brain-cancer.jpg Olivia Newton-John, who became an advocate for breast cancer research after she was diagnosed with it two decades ago and underwent a double mastectomy, has revealed that her sister Rona Newton-John (above, left) passed away last Friday (May 24) from brain cancer.

Rona was diagnosed just a few weeks ago, causing Olivia to postpone her Las Vegas show so the sisters could spend time together.

Olivia writes on Facebook:

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. 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.

In lieu of flowers the family would appreciate donations to the ONJCWC where a brain tumor wellness program will be started in her name. Thank you all for your kind words of love and support.

Love and light,

Newton-John also includes a link to the brain tumor wellness program, if you'd like to donate.

Photo/Video credit: Getty Images