The ice-cream van was a nostalgic distraction as the work on Deathly Hallows Part 1, out this month, and Part 2, out next July, drew to a close. For the three actors who have given their teenage years to the mammoth film project, there’s also a curious sense of relief. Harry, Hermione and Ron – and their other halves Daniel Radcliffe, Emma Watson and Grint – are free at last.

“It felt like the last day at school,” says Grint. “Packing up all the stuff in my dressing room, all the old toys still there from when I was 11… I’d underestimated how emotional it would be. We all cried.”

“I suppose when they selected us as kids, they weren’t expecting us to act that much. They didn’t really want kids from drama school. I always felt quite a strong connection to Ron. I don’t know if it was just a ginger thing though,” he says, laughing. His hair is actually less carroty in real life: “Yes, the sun calms it down a little bit.” As for the Rupert-Ron intermingling, he says: “Possibly I’ve taken on some of his characteristics and we have merged into the same kind of person.”

“When he first started he was really cute and really shy,” recalls Julie Walters, who has played Grint’s screen mum Molly Weasley from the start. “My abiding memory of him is at the first premiere and Grant, my husband, and I looked at Rupert and there was a beautiful little moon face, and he looked like a rabbit caught in the flashbulbs. He was such a sweetheart you wanted to cuddle him.”

“Alan Rickman [who plays the menacing Severus Snape] fascinates me,” says Grint. “He always seems to be in character. He’s really quite intimidating with that air about him. Actually, he’s nice to talk to, but he’s got this presence that makes you feel like he’s unapproachable.” Julie Walters is one of his favourites. “I’m quite close to her. She’s warm. She really is like my mum, and she’s seen us grow up.”

“My part really improves,” says Grint. “It’s more complicated. Ron has a total freak-out, and gets jealous and angry. There’s a lot of paranoia and grief, and he falls in love. It’s quite a big moment for him.”

The final book and this film also include the first kiss between Ron and Hermione, a relief for frustrated viewers. Rowling hinted at an attraction between the two for a long time, and there were petty jealousies and near misses. “The kiss happened quite naturally, and in the second part of Deathly Hallows they’re really quite couply, holding hands a lot. It wasn’t like it came from nowhere. It was quite a tricky kiss, a bit strange, but quite sweet really. It was just one shot, but we had about six takes. It was all right, yeah. Easy after the first take,” says Grint, then adds, “I’ve almost no memory of it at all.”

Grint often gets followed down the street or accosted in bars. When he goes with his mates to rock festivals, he has been known to wear a duck mask, just so he can walk around freely.

“You develop an instinct for it. You can hear people saying your name, feel their stares. But it depends where you are. Here in Britain, people are a lot more reserved. In America it’s kind of crazy: louder, a few screams, and they want me to sign stuff – them. I once signed a tattoo of me, Dan and Emma on a guy’s arm. He was quite an old guy, 40, freaky, quite weird. It wasn’t a great tattoo either. I looked a bit like Anne Robinson.”