Although it's long been known Grant is Trixie's father, the popular presenter has always remained silent on the matter. However on Monday evening, Fifi shared two touching photos of her darling daughter Trixie playing with her dad.
In one shot, Grant plays peek-a-boo with the cute toddler.
In another image, Grant cuddles Trixie as she erupts into a fit of giggles.
"Bouncing castle daddy cuddles," the 39-year-old captioned the sweet photo.
The family snaps look to be taken at Trixie's third birthday party.
In an earlier post, The Project star shared the intricate Minnie Mouse birthday cake she'd made for the celebrations and joked: "Carrying my daughter for nine months was easier than making this cake."
It didn't take long for fans to commend the star. "Wish more co-parents could be like this," one user said.
"Beautiful pic, beautiful moment," another added.
Fifi and Grant secretly dated in 2012 but broke up just before the 39-year-old revealed she was pregnant with her first child.
Watch Fifi introduce her newborn daughter on Sunrise back in 2013 below. Post continues after the video!
The pair have never commented on their tryst. Trixie is often spotted with her look-alike half-siblings Jamie, 26, Morgan, 23 and Jett, 19, who Grant shares with former wife Lisa Curry.
Speaking to Woman's Day in 2014 about life as a new dad, Grant said: "I'm very happy."
For Fifi, her daughter is the centre of her universe.
"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," she explained to The Daily Telegraph.
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Australian Women's WeeklyYesterday 11:49am