Olivia Newton-John's Sister Diagnosed WIth Brain Cancer---Olivia Survived Her Own Breast Cancer

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

Olivia Newton-John is coming to the aid of her older sister, who has been diagnosed with the destructive illness.

Rona Newton-John, 69 is 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 has postponed moving to Las Vegas  to be with her sister in this troublesome time.

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 is postponing her gig at Vegas' Flamingo hotel filling in for Donny & Marie Osmond's away dates even before tickets go on sale.

Olivia has had to jump through so many obstacles in her life, including her husband staging his own death to avoid paying debts and enable his teenage son to cash in on a $151,000 insurance policy.

The blond actress has survived it all and come through stronger than before and her sister's illness will be no exception.