Dame Olivia Newton-John's heartbroken husband John Easterling has paid tribute to “the most courageous woman I have ever known”, following her death on Monday 8 August. John announced via Facebook and Instagram that Olivia, best known for playing Sandy in the 1978 hit film Grease opposite John Travolta, had passed away peacefully aged 73 at her Southern California ranch in the early hours of Monday after battling cancer on and off for 30 years. John has once again taken to Olivia's official Facebook page to post a heart-wrenching but uplifting tribute to Olivia, saying that she was “the most courageous woman I have ever known” and that her caring nature “almost eclipses what is humanly possible”.