My life has a very distinct before-and-after line. Before June 2000 I went to a normal state school and life was ordinary. My dad sold Formula One memorabilia and my mum made wedding cakes and looked after five kids. I was very grounded. When I got the part of Ron Weasley I left school straight away and things have never been the same.

I was quite a shy kid and acting was always attractive to me because you could hide behind the character and be someone completely different. I did loads of school plays and fêtes, and I once dressed up as Mystic Meg.

For the first few Harry Potter films I was living the dream. The reason I auditioned was because I loved the books. When I got to film three or four, I started to feel an overwhelming weight of responsibility because they were so phenomenally popular. The whole press and red carpet thing was an attack on the senses. I don’t excel in that kind of environment.

I feared God as a kid. I went to a Hertfordshire Catholic school. The stories were very powerful and I took them all on board even though I’m from a very secular family. I knew I wasn’t one of them, but I was quite anxious and worried about religion and the dogma attached to it.

There were definitely times when I thought about leaving. Filming Harry Potter was a massive sacrifice; working from such a young age for such long periods and I definitely remember thinking during one extended break, ‘This whole thing is so all consuming, do I really want to go back? Maybe it’s just not for me.’ I guess I was probably just being a teenager.

As I got older I could feel this growing narrative willing me to get engulfed in some big scandal off-screen. It felt like people were waiting for me to go off the rails, but it was never going to happen. We filmed the whole thing in this very intense bubble in Watford not Hollywood, so we didn’t have the chance to discover drugs, or anything like that.

I’m naturally an introvert, but there is something about standing out – being in the limelight – that I enjoy, a little bit.

Finishing Harry Potter was surreal. It was a very strange feeling but it came at the right time as we were all ready to move on but after the final shot it was quite weird to think that was it. It was disarming and at that point I didn’t really know what was happening. I felt a bit lost.

The line between Ron and me became thinner with each film and I think we became virtually the same person. There’s a lot of me in Ron and moving on was a massive adjustment because it was such a constant part of my life. I don’t want to liken it to coming out of prison because it wasn’t a prison, but it did feel like stepping out of an institution. It was nice to breathe the fresh air and now I’m really enjoying stepping further away from that blue-screen world.

I peaked pretty early, but I’m fine with that. It would be ridiculous to think that you can replicate that level of success. It’s always going to be a challenge, but I’m kind of enjoying that. It’s quite fun to surprise people.

Turning 30 felt strange. It just doesn’t feel like I’m there yet and I don’t know what the future holds. I’m just going to go with the flow, keep playing interesting characters and see what happens. I’d like to settle down and have kids soon. If I had a son, would I call him Ron? It’s quite a good name, but probably not. And Grint’s a tough name to pair a one-syllable first name with.

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