The singer took to Instagram to show her appreciation for the actress on her 70th birthday.
‘Happiest of birthdays to the one and only ONJ!!!!’ Kylie wrote.
The pair share a close bond and have supported each other throughout each of their cancer diagnoses.
ONJ was delivered the devastating news that she first had cancer back in 1992 before another cancer appeared in her shoulder in 2013.
She kept the second blow of bad news to herself, but didn’t hold back when her good friend was diagnosed with breast cancer in 2005.
‘I feel so badly for Kylie, and my heart goes out to her,' ONJ said at the time. ‘It is a very, very difficult time. It is also a wake-up call for all of us women to examine ourselves.’
Having suffered and survived the same illness, ONJ was a pillar of support for her fellow star.
‘Heartfelt thanks to the incredible number of people who have sent messages of love and support,’ Kylie said in a statement after receiving her diagnosis. ‘I would also like to extend my best wishes to all of the other women around Australia and around the world dealing with the same illness.’
Sadly, ONJ broke the news earlier this month that her cancer had returned. ‘I’m still treating it, and I’m treating it naturally and doing really well,’ she said in an interview with Channel 7’s Sunday Night, revealing she is treating her symptoms with ‘natural’ therapies after undergoing radiation treatment.
‘I’m very lucky that I live in a state where it’s legal and that I have a husband that is a plant-medicine man.’