Grease star, singer, and activist Olivia Newton-John passed away Monday morning at her Southern California ranch. Surrounded by family and friends, the performer passed peacefully at the age of 73, her husband confirmed on social media.

Known best for her role as Sandy in the hit film Grease, the actress, singer, and activist has been open about her experience with breast cancer. Over the course of her decades-long battle, the star started the Olivia Newton-John Foundation Fund, which has been dedicated to researching plant medicine and how it can be used for cancer treatments.

RELATED: Lady Gaga Officially Confirms Joker 2 Role Via Musical Teaser

"Dame Olivia Newton-John (73) passed away peacefully at her Ranch in Southern California this morning, surrounded by family and friends. We ask that everyone please respect the family’s privacy during this very difficult time," her husband, John Easterling, shared on her official Facebook page. "Olivia has been a symbol of triumphs and hope for over 30 years sharing her journey with breast cancer. Her healing inspiration and pioneering experience with plant medicine continues with the Olivia Newton-John Foundation Fund, dedicated to researching plant medicine and cancer. In lieu of flowers, the family asks that any donations be made in her memory to the Olivia Newton-John Foundation Fund (ONJFoundationFund.org)." As noted in the statement, "Olivia is survived by her husband John Easterling; daughter Chloe Lattanzi; sister Sarah Newton-John; brother Toby Newton-John; nieces and nephews Tottie, Fiona and Brett Goldsmith; Emerson, Charlie, Zac, Jeremy, Randall, and Pierz Newton-John; Jude Newton-Stock, Layla Lee; Kira and Tasha Edelstein; and Brin and Valerie Hall."

In response to the tragic news, Newton-John's Grease co-star John Travolta took to Instagram to share a message for his Sandy. "My dearest Olivia, you made all of our lives so much better. Your impact was incredible," Travolta captioned the post. "I love you so much. We will see you down the road and we will all be together again. Yours from the first moment I saw you and forever! Your Danny, your John!" The duo played the iconic roles of Danny and Sandy in the film. The actors reunited years later to film Two of a Kind in 1983 and have appeared to be close friends for all these years.

Newton-John held the belief that plant-based therapies could improve the quality of life for those who are seeking cancer treatments. She and her husband launched the foundation in October 2020 with the goal of helping people realize "a world beyond cancer," as their mission statement says. The current research that the foundation is doing could help improve the lives of many cancer patients and figure out how plant medicine treats cancerous cells.

Grease is now streaming on Paramount Plus.

MORE: The Best Musical Moment From Each Season Of Stranger Things

Source: Olivia Newton-John/Facebook