Grint was on the Tonight Show with Jimmy Fallon last night discussing his series 'The Servant'. But, of course, it wasn't too long before 'Harry Potter' was brought up.
Fallon asked the former child-star about reuniting with the cast for the 20 year anniversary in 'A Return to Hogwarts'.
"We just kind of clicked straight back into how it was. It's been ten years since we wrapped the last movie and yeah, time has passed. I do feel like an old man now."
He is far from old of course, at only 33. But, the fact that Ron Weasley now has a child has aged us slightly. Fallon mentioned that Grint had joined Instagram, breaking a Guinness World Record for quickest time to reach 1 million followers.
"I never know what to post! It's mainly 'Servant' trailers and the back of my daughters head. "
His first post introduced us to his now 21-month old daughter Wednesday G. Grant. Fallon asked about the unusual name and what it was inspired by.
"I'm always hesitant to say it was 'The Addams Family'... But yeah it was the 'The Addams Family.'"
And the G? The inspiration behind that was none other than Samuel L. Jackson. "We love the idea like the initial, like Samuel. L Jackson, Michael J. Fox. That kind of speaking the initial."
"Now you have this beautiful baby and one day you're gonna show her these movies one day and say 'that's daddy!'" said Fallon.
Grint replied, "I've already started showing her the trailers. She has a wand and a PEZ dispenser with my head on it."
Have a look at Grint's full chat with Jimmy Fallon below: