From first meeting Olivia Newton-John in New York when she was just seven years old, to portraying the Grease star in a biopic, it's fair to say that ONJ has made a lasting impact on Delta Goodrem.
And now, almost six months on from the passing of Olivia, aged 73, Delta has been able to pay tribute to her self-confessed hero the best way she knows how - by singing.
Last night at the annual G'Day USA Gala in Los Angeles, hosted by the American Australian Association, Delta took to the stage for a special tribute to her idol.
The awards night celebrates Australians who are prominent in the U.S. entertainment industry, and works to highlight figures from film, television, music and pop culture who have enhanced Hollywood-Australia relations.
A melody of Olivia Newton-John's greatest hits was performed by Delta Goodrem, with Olivia's husband, John Easterling, and daughter, Chloe Lattanzi, on hand for the musical tribute.
Sam Worthington, Miranda Kerr and Paul Hogan were other notable Australian celebrities at the event, whilst American pop-star Katy Perry also attended and posted a clip of Delta's performance to her Instagram stories.
Hogan also paid tribute to ONJ, saying that "every day with Olivia was supernatural".
Speaking about ONJ following her death August 2022, Delta told Sunrise about the special first moment that the two songstresses met.
"All of a sudden Sandy from Grease walks in the door… the world stopped and I said, 'Sandy's there mum. It's Sandy!'," Goodrem recalled on Sunrise.
Olivia heard the accent and struck up a conversation, even telling Delta she hoped to see her tomorrow.
"I was looking for her always," Delta said of the moment, though she couldn't have known how close they'd become.