The singer went on to honour Emma with the sweetest words.
"She ensured my stay was safe and comfortable, always had practical advice for me, showed strong leadership skills and had a great sense of humour.
"She was a bright, energetic and powerful woman with a huge future ahead of her, and we connected on our mission to help patients on their cancer journey.
"Emma had such a generous spirit and a warm and loving heart - I will miss seeing her lovely face at the Centre and send my love and deepest condolences to her friends and family.
Followers of the singer were quick to share their support for Olivia's loss.
"Oh, no. I'm so very sorry to hear of this loss for you, her family and the Centre. My sympathies 🙏🏼" journalist Leeza Gibbons wrote in the comments section.
"So sad to hear she took care of my dad who sadly passed away recently. May she RIP 🙏🏻" another added.
"Sending love to you and all of Emma’s friends and family. May she rest in peace 😢❤️" a third penned.
In October 2020, during Breast Cancer Awareness month, Olivia launched the ONJ foundation to advocate for “kinder” treatments for cancer.
Speaking in a video introducing the foundation, the actress shared her own breast cancer survival story, detailing the moments after she was first diagnosed.
“I knew immediately something was wrong,” Olivia said.
“I had a mammogram. The mammogram was benign and I had a needle biopsy that was also benign. I don’t say this to scare women, but you have to just trust your instincts.”