"Four years to the day and still as true as ever. Happy birthday to our special little Ruby🎂4️⃣," he captioned the black and white photo of his little girl.
While her face isn't in the shot, it's not uncommon for the protective father to have hidden her head – probably due to privacy.
Back in September McManus, 43, shared a picture of Ruby's tee which read: "I <3 Daddy".
"The feeling is mutual 💗 #FathersDay." he captioned the cute picture.
In the past, McManus has opened up about his role as a father and how his life has changed since she arrived.
"It is like having a little present that you get to keep on unwrapping, almost on a daily basis, and there’s always another great thing inside," he told The Australian.
Too sweet! McManus shares his daughter with wife Tasma Walton.