Beloved singer and actress Olivia Newton-John has died at the age of 73 following her decades-long battle with breast cancer. Tributes have been pouring in from celebrities around the world since the announcement of her death. Her Grease co-star John Travolta shared a photo of a young Newton-John and described her impact on the world as "incredible." Director James Gunn also paid tribute to the star and shared that he had previously lived in the house she built in Malibu. Kylie Minogue said she always looked up to Newton-John, and she was and always will be an inspiration to her. While Viola Davis thanked Newton-John for all the eternal memories she created for everyone. Director Edgar Wright said she dominated the charts so much that "it felt like she WAS pop music." Sir Rod Stewart described Newton-John as the "perfect lady, gorgeous, with great poise and with a certain Aussie sophistication."