The 28-year-old singer was up against finalists Natalie Bassingthwaighte and Dane Swan and ended up winning $100,000 for her charity, the Starlight Foundation.
The gracious star was thrilled when hosts Dr Chris Brown and Julia Morris announced the news.
“Thank you so much,” she said tearfully.
“Mine is the Starlight Foundation and helping young kids and early teenagers smile,” she said.
“Be happy. Have their minds get taken out of a hospital bed, a room, help families in need and bring laughter and joy and happiness to what can be a horrible time.”
After six weeks in the jungle, Donovan was thrilled to discover she’d lost a whopping 17 kilos after a challenge involving scales.
“Casey, you started at 149, you are now 132. That's 17 kilograms,” Doctor Riesa Jansen van Rensburg announced.
“'[I]didn't expect 17. I was maybe thinking 5 or 8, so yeah. [I'm] happy,” she responded.
The singer revealed her goal weight was to get under 100 kilos.
Her fellow contestant Kris Smith offered his advice and promised to help keep her on track outside the jungle.
“I want to know, fellow Sydney sider, how I can help. Even if it's just meeting up and going for a walk, even if it's meeting up and just talking about your diet, even if it's just a phone call and you go, ‘Look, struggling, how can I get past this part,” he said.