The 32-year-old Harry Potter star and his girlfriend, actor Georgia Groome, welcomed their first child together in May.
Grint ‘s post is of him sitting on a yellow chair wearing a baseball cap and a black T-shirt, with Wednesday, his daughter sleeping on his chest in a pink onesie.
“Hey Instagram….only 10 years late, but here I am,” Grint captioned the post. “Grint on the Gram! Here to introduce you all to Wednesday G. Grint. Stay safe, Rupert.”