The proud mama took to Instagram to share a series of shots from her daughter's birthday celebrations.
The 40-year-old threw Trixie Belle a Minnie Mouse-themed bash, with the girl of the moment dressing up as the cute character.
The radio personality was clearly overwhelmed by the significance of the day, sharing a stunning tribute to her only child.
"My baby's four!! How did this happen so fast?! I could not possibly love this beautiful, gentle little angel anymore, she is my absolute everything. Everything," The Project star penned.
While the day was a complete success, it didn't come without some hiccups.
Fifi revealed that her mini-me originally "requested a fairy party [but] at the last minute she wanted a Minnie Mouse dress."
Thankfully the mother-of-one managed to pull off a last-minute hustle and give her little girl the fairytale-day she wanted.
The Neighbours actress even made a Mickey Mouse cake.
"I knew I'd made a mistake when I let Trixie scroll through the online images of Minnie Mouse cakes and she wanted Minnie in a car," she confessed.
"Anyway after a week of baking/freezing/baking/freezing, and despite dodgy wheels I was pretty happy with the result."
Fifi welcomed her daughter on April 5 back in 2013.
"I've had a baby," she told Hamish Blake, Andy Lee and Jules Lund at the time.
"It's a little girl. She came into the world at 2.30 this afternoon. What's happened is, and you guys will find this hard to believe because you know me so well.. I've sort of been caught off guard and I don't have the name ready."
"She's absolutely amazing, I know that everyone says this, but she just perfect," she gushed.
Last year, the TV personality confirmed what was long known - that Grant Kenny is Trixie's father.
They decided to address the topic of Trixie's paternity during her third birthday by sharing a series of family snaps.
Fifi and Grant secretly dated in 2012 but broke up just before the 39-year-old revealed she was pregnant with her first child.
Speaking to Woman's Day in 2014 about life as a new dad, Grant said, "I'm very happy."
The ironman, who was previously married to former Australian swimmer Lisa Curry, is also dad to their three kids, Jaimi, Morgan, and Jett.
The trio would have no doubt have spoiled their little sister on her birthday.
In the past, the actress has mused that her daughter is her world.
“Motherhood is the biggest blessing. It sounds so cheesy, but it really is!"
After welcoming her little one, Fifi remarked, "It really is as if my life has just begun.”
Chatting to the Daily Telegraph, the Aussie personality admitted, “I’m too busy being a working mum to focus on anything other than my precious little girl.”
“She means the world to me and I’m doing all I can to protect her and ensure she has a happy, stress-free, easy path in life, just what any parent wants for their child.”
Happy birthday Trixie!