John Travolta says Olivia Newton-John made everyone's 'lives so much better'

John Travolta has posted a heartbreaking tribute to his Grease co-star Olivia Newton-John after the Australian icon died.

The singer and actor's family revealed she died peacefully at her home in southern California at the age of 73.

Celebrities all around the world have paid their condolences to Newton-John.

Travolta was one of many who wrote kind words about his co-star and said the world has become a little less colourful.

"My dearest Olivia, you made all of our lives so much better," he wrote on Instagram.

"Your impact was incredible. 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 73-year-old's death was revealed in a statement on her social media account.

Her husband, John Easterling, told the world the heartbreaking news while also celebrating everything she did in her life.

"Dame Olivia Newton-John (73) passed away peacefully at her Ranch in Southern California this morning, surrounded by family and friends," he said.

"We ask that everyone please respect the family’s privacy during this very difficult time. 

"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."

The statement was followed up by a post from Olivia's daughter, Chloe Lattanzi.

She said: "I worship this woman. My mother. My best friend."

Newton-John was first diagnosed with breast cancer in 1992 when she was just 43 years old, and announced in 2017 that it had returned while also revealing she had privately dealt another diagnosis of the disease in 2013.

Throughout her diagnosis, she underwent numerous treatments, including a mastectomy, chemotherapy and breast reconstruction.

Since her first diagnosis, the Grease star had championed the cause of raising awareness for breast cancer, and in 2008 built the Olivia Newton-John Cancer and Wellness Centre in Melbourne, Australia.

Newton-John used her profile to raise awareness for plant-based medicine, and she supported several charities and causes during her life.