"No one is more surprised than me that I did this already."
Chrissie said she is now "doubling down" and will strive to walk 300km over the entire month of August.
"Will I be able to do it? I really don’t know. But I’m going to give it my best shot," she said.
The mother-of-three revealed that a company, who remains anonymous, has offered to match her followers' donations for the next $15,000.
Chrissie has remained open and honest about her health journey since finding fame on Big Brother in 2003.
Back in 2010, she credited Jenny Craig for helping her drop 50kg, and in 2015 she lost a further 15kg after competing on I’m a Celebrity... Get Me Out of Here!.
The radio star is no stranger to a busy schedule, but manages to balance her career, motherhood, and time for herself.
"For me, this year’s really been the first year that I’ve taken [health] seriously," she told WHO last month.
"Working mothers, or mothers in general, or women in general, we just don’t take the time to try and work it out and we just sort of roll with the punches."
She eventually worked out that sleep was probably her "biggest issue", as she hasn't had enough sleep for about 20 years.
"Ever since I started in breakfast radio and then the kids come along, and so I started prioritising sleep this year and it has made a huge difference," Chrissie said.
"Some days it’s just about listening to your body and what it needs and giving it what it needs."
In recent months, Chrissie has credited a combination of things for losing the additional weight, including a focus on “me time”, giving up alcohol and getting her daily step count up.
Melbourne’s harrowing 112-day lockdown last year is said to have inspired the mum of three’s sobriety.
“I’ve never done anything about it, until now. Learning how to meditate kicked it off for me and I realised after the first 10-minute block that it was the first time in ages I’d stopped and slowed down, with my own wellbeing top of mind,” Chrissie explained on Instagram.
Chrissie takes life day by day and tries to fit in a few things for herself each day, even if it's just 15 minutes of reading a book or putting on a face mask.
"Your life changes so much when you have kids, that the older they get, the further away from remembering what you actually liked to do comes into play," she said.
"I spend so much time making everyone’s life so easy and organised and I’ve really forgotten what I enjoy. So, I had to make a list, took me about a week to think of things."