"Oh little Sunday the fun you’re going to have with these 2 by your side. #lovedforever," Grant wrote.
The post was met with a lot of love from the presenter's friends and fans.
Grant's former I'm A Celebrity... Get Me Out of Here! co-star Pettifleur Berenger commented a sweet but simple "😍😍😍."
Just six days ago, The former Family Feud host admitted that missing watching some of Sunday's milestones was tricky.
"The hard part about working away is missing my girls. This one is changing so quickly. She’s even grown some hair since I left," Grant wrote alongside a picture of adorable little Sunday.
WATCH: Grant and Chezzi Denyer's daughters meet their baby sister (Article continues after video)
Chezzi was quick to reply to her husband's post, penning: "We miss YOU 😘 but how great we can FaceTime every single day xoxooxoxox."
Grant and Chezzi announced the safe arrival of Sunday back in February this year. In the Instagram post, the proud mum-of-three said that the bub looked "a lot like Sailor, but mostly she looks like Daddy."
The Denyer clan never cease to make us smile.
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