Sad news for Olivia Newton-John's family.
The Grease star's older sister, Rona Newton-John, died Friday at age 70 after battling an aggressive brain tumor she was just diagnosed with last month.
Olivia, who is a breast-cancer survivor, confirmed the news on her Facebook page Wednesday.
"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," she wrote.