Olivia Newton-John Dies At 73

After battling breast cancer three times over the past 30 years, Olivia Newton-John has died at the age of 73. The Australian singer is best known for her song "Physical" and for playing Sandy in the hit 1978 movie "Grease" with John Travolta. Her family announced her death on Twitter: "Dame Olivia Newton-John passed away peacefully at her Ranch in Southern California this morning, surrounded by family and friends."