The Chicks perform live 'Hopelessly Devoted to You' cover in heartfelt tribute to Olivia Newton-John

As celebrities around the world continue to honour to the beloved Olivia Newton-John after she passed away last week, The Chicks (formerly the Dixie Chicks) surprised fans at their concert on Saturday night with a heartful tribute to the Australian icon.

Taking to the stage at the Gorge Amphitheatre in Washington state, the trio belted out a powerful rendition of 'Hopelessly Devoted to You,' first crooned by Newton-John's character, Sandy Olsson, in Grease.

Before the performance, singer Natalie Maines told the audience: "We lost a worldwide sweetheart last week, Olivia Newton-John. I thought I was Olivia Newton-John from like [ages] 4 to 12, and then I just wished I was Olivia Newton-John ... Feel free to sing along."

And the audience did indeed join Maines in singing the melodramatic lyrics to the classic ballad.

'Hopelessly Devoted to You' was a major hit for Newton-John in 1978, reaching the number three spot on the US Billboard Hot 100 and number 20 on the country chart. 

Newton-John died in the morning of Monday 8 August at her ranch in Southern California, where she was surrounded by family and friends.

While a specific cause of death has not yet been revealed, a source close to TMZ reported that "she lost her battle to metastatic breast cancer."

The 'Physical' hitmaker is survived by her husband, John Easterling, who shared the news of her death on her official Instagram account, and her daughter, Chloe.