Australian singer-songwriter Delta Goodrem was lucky enough to call Newton-John her "mentor". Sharing two intimate photos of her besides her idol, the 37-year-old wrote on Instagram: "The whole world will feel this heartbreak today because the entire world felt Olivia's unmatched light. A force for good. A force of nature. Strong and kind. my mentor, my friend, my inspiration, someone who always guided me… she was always there for me. Family to me. I don't have all the words I would like to say today but I hope everyone will join in celebrating our beloved Olivia, her heart, soul, talent, courage, grace…I love you forever ❤️"