The Aussie icon passed away peacefully at the age of 73 at her home in Southern California, surrounded by her family and friends, after a decades-long battle with breast cancer.
Olivia's husband John Easterling broke the news on Tuesday morning in a social media post.
Tottie revealed that Olivia's health began worsening in the week leading to her death, adding it was "not a shock" to the family as she was "really skinny and unwell" in her final days.
"It's not a shock, we've known how sick she's been, especially in the last five days," Tottie told Tracy Grimshaw.
Speaking of her final goodbye with Olivia, the actress and singer shared, "I couldn't get to America in time and I wanted to say goodbye, so I asked [John] if he could hold the phone up to her ear, but he got me on FaceTime so I managed to see her."
The former I'm A Celeb star added, "I told her all the things I needed to say."
Speaking of her relationship with Olivia, Tottie described the star as being "more than a mother to us".
"Just getting those words out... I mean she was leaving us, this was only the day before yesterday, but I could feel that she got it and it landed, so that really helped," she added of her farewell.
Tottie also shared that Olivia "really struggled with a lot of pain" in her final years and while the family knew her condition was worsening, they were still optimistic that she might turn a corner and be healthy again.
"But it wasn't just the cancer that got her, it was other complications," Tottie said. "Being in a hospital and with a very susceptible immune system, she got secondary infections."
Tottie added that even when Olivia was very unwell, she was never scared of dying because of all that she had done with her life.
"She said, 'I'm not afraid, I've done more in my life than I could have ever imagined,'" Tottie said, adding her work with cancer research is what kept her going.
When asked by Tracy what Olivia was most proud of, Tottie broke down, as she answered, "Chloe... she loved that girl, and her husband, and all of us and the work she did, but Chloe, she just loved that girl so much."
After Victorian Premier Dan Andrews offered Olivia's family a state funeral, Tottie revealed that they will be accepting it.
"We will, on behalf of, not just our family, but I think Australia needs it," she said. "I think our country needs it, so we're going to accept it and I won't cry at that, I'm so sorry."
Never miss a thing. Sign up to Yahoo Lifestyle’s daily newsletter.
Or if you have a story idea, email us at firstname.lastname@example.org.