IN CASE YOU MISSED IT: John Travolta leads tributes to Olivia Newton-John

John Travolta has paid an emotional tribute to his late Grease co-star Olivia Newton-John. The legendary actress/singer passed away peacefully at her ranch in Southern California on Monday morning following a battle with cancer. She was 73. Taking to Instagram, Travolta was one of the first to honour Newton-John, whom he famously appeared alongside in the 1978 film Grease. In addition, a number of other celebrities have honoured Newton-John. "Too young to leave this world. May she RIP," wrote Barbra Streisand on her Instagram page.