The older sister of Olivia Newton-John, Rona, dies of brain cancer. The 70-year-old model and actress was diagnosed with brain cancer last month and finally lost her battle.  Rona Newton-John died on May 24^th in LA. Olivia has survived so many life struggles including beating her own cancer. It must be so heartbreaking to lose a sister, but Olivia Newton-John is a survivor and will come through.

As her sister dies, Olivia Newton-John takes to Facebook to tell the world about Rona:

"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 has asked donations be sent to the Olivia Newton-John Cancer & Wellness Centre. A brain tumor fund will be set up in Rona's memory and the funds will go to helping people battling the disease.

Olivia Newton-John revealed her older sister has been diagnosed with brain cancer the the end of April. The "Grease" star had her own battle with breast cancer in 1992 and happily has been cancer free since 2004.

Olivia Newton-John went to the aid of her older sister, who was diagnosed with the destructive illness.

Rona Newton-John, 69 was also an actress playing a small roll on "The Benny Hill Show." She was married to Olivia's Grease co-star Jeff Conaway from 1980 to 1985.

They have a son, Emmerson, 38, who is a race car driver. Conaway, who struggled with substance abuse, died in 2011 from complications related to pneumonia and the degenerative brain condition.

64-year-old Olivia had postponed moving to Las Vegas to be with her sister in April and is certainly glad she made that decision.

Olivia Newton John publicly stated:

"I recently received the very sad news that my beautiful sister, Rona Newton-John, has been diagnosed with brain cancer.  In light of this news, I have decided to postpone my forthcoming Las Vegas residency to spend time with her and our family. 'I want to thank everyone in advance for respecting our privacy during this difficult time."

The Australian pop singer postponed her gig at Vegas' Flamingo hotel filling in for Donny & Marie Osmond's away dates even before tickets went on sale.

Olivia has had to endure  so many obstacles in her life, including her own cancer and her husband staging his own death to avoid paying debts.

Olivia has made it though all of the hardships in her life and the death of her sister will be no exception.