Matthew Lewis in Toronto. (George Pimentel/GETTY IMAGES)

“The press tour is a way for me to say goodbye, to be honest. It’s been absolutely fantastic for the last 11 years,” Lewis said. “And whenever something that you do [is] that much fun, and you do it for that amount of time, it’s obviously a great shame that it comes to an end. But I’ve had a good run.”

Quite a “good run.” Since he was 11, Lewis has played Neville Longbottom, an introverted student at Hogwarts-turned hero wizard, in all eight “Harry Potter” films alongside Daniel Radcliffe, Emma Watson and Rupert Grint

“It’s a bit like leaving school in terms that I’ve made some great friends, had great experiences and had a lovely time. But now it’s the next chapter,” Lewis said. “For the first time in over a decade I don’t know what’s happening next and that’s exciting.

“I think if you’d asked me a few years ago it would have been different, very different. I’d been clinging onto J.K. Rowling’s legs.”

During the more than a decade that Lewis has been playing Neville, the actor has only had one other film role. More recently, he starred in a stage production of Agatha Christie’s “Verdict,” something the actor said gave him the “boost” he needed to look forward to the future. But, of course, he wouldn’t be where he is today without Neville.

“Neville helped me grow up as much as he’s helped people who’ve watched the films,” he said. “When I first started, Neville and I were very similar: shy, chubby-faced boy. There was very little acting in the first couple of movies. That’s just me.

“But as he grew, so did I. And the thing about Neville is this amazing message that J.K. Rowling did for him. This message of evolution,” Lewis said. “Neville’s bullied, he’s scared of his own shadow. No one ever thinks he’ll amount to anything. And here he is in [“Deathly Hallows — Part 2”] saving the wizarding world. It just shows you that, no matter how your childhood is, it doesn’t define you.”

From left, Matthew Lewis as Neville Longbottom, Emma Watson as Hermione Granger, Rupert Grint as Ron Weasley and Daniel Radcliffe as Harry Potter. (Jaap Buitendijk/JAAP BUITENDIJK)

(Warning: This next section contains minor spoilers.)

In “Death Hallows — Part 2,” Neville proves to be an unlikely hero, saving the day more than once. In the final Battle of Hogwarts, he confronts Lord Voldemort and destroys the Dark Lord’s snake that serves as the final horcrux, an item where part of his soul is hidden. The film gives Lewis the best opportunity to show off his acting chops, so is it any wonder that’s it’s his favorite?

“I had all the action stuff, I had the rousing speech to do. I had the humor still,” he said of his role. “And working along with Ralph Fiennes ]who plays Voldemort], it challenges you. ... I felt like I was being pushed and I loved it.”

While the actor was hoping fans would notice his performance, he’s been getting attention for something unexpected: his looks. “It baffles me. It renders me rather speechless,” said Lewis, who wore body padding and prosthetic ears and teeth in the “Potter” films. “But don’t get me wrong, it’s so lovely.”

Lewis had to tell his publicist to stop sending him clips: “I won’t be able to fit my head through most doors if you keep sending me this stuff.

“I think everyone’s gone insane and should go speak to a doctor. But it’s very lovely. But I don’t really know what to make of it.”

Lewis said he’s received a lot of mail from people who relate to Neville’s struggles at school, as well as the odd marriage proposal. On the weirder side, he was given a yellow bell pepper with text carved into it: “It looked like the inside of a prison cell. It was very odd. I mean, it was sweet — the thought I mean. Not the pepper,” he joked.

He’s garnered a loyal following that regularly updates his fan site. But now the actor’s using his Twitter account to reach out to fans, to their delight.

What started as a way to communicate with his non-actor friends in Leeds, his hometown, turned into something completely different when a fan site learned of its existence. And despite feeling a little “pressure” from the attention, Lewis is now committed to his 116,000-plus followers, reading each tweet: “They don’t realize what it means sometimes to hear the nice things they say.”

The amount of attention paid to Lewis has increased with the release of the final film, he said. Now the young actor who feels that he lives two lives — one in London, the other in Leeds — is on the verge of larger stardom.

“It’s suddenly very overwhelming, he said, adding that the experience has given him even more admiration for Radcliffe. “It’s made me aware of how, times it by a hundred, by a thousand, it must be what Dan experiences. I’ve had a small fraction of that over the past ten days and it’s difficult.”

Indeed, Lewis came to Radcliffe’s defense when a quote about the actor’s reliance on alcohol spread on the Internet, he believes unfairly.

“It bothered me because Daniel works so bloody hard on these films. And he’s so famous and gets such a following,” he said. “Yet he’s not changed from the day I met him. His feet are so on the ground. And I think that’s so inspiring.”

For now, Lewis will continue the press tour, traveling to Australia where he’ll finally get some downtime. He doesn’t have any concrete plans for the future, but said he has been getting new scripts in his e-mail inbox. “I’ve no time to read them, but I will get through them and try to get some more work.”

“I’ve never really had this before,” he said. “I’m very overwhelmed by it all.”

More on “Harry Potter” from The Washington Post:

Review: “Harry Potter and the Deathly Hallows — Part 2

Why is the world so wild about Harry?

The Harry Potter generation’s years of waiting are over