"It's strange," he told us. "I was made to feel very welcome, but I was there for a specific part that required just one scene and then pop up once with a wand, but apart from that, it's just one scene with a little dialogue to give some exposition about Dumbledore's past life.

I had the joy of sharing the scene with three... well, they're not kids anymore... Daniel Radcliffe, Emma Watson and Rupert Grint. They were very charming, very gracious, made you feel very welcome and you're aware. Here I am at a certain age with all my experience and these kids really know what they're doing, they know their characters and here I am saying, 'Who the hell am I... apart from Michael Gambon's brother?'

It's a lovely experience and the director is a very soft Yorkshire man, he's not one of these guys, 'Come on!' It's very considered and thought about. I saw him working with the younger ones, giving them little pointers, never pushing, just suggesting about development, and here I am, part of what everyone has to offer. You really have to say they're confident and they know who they are, they know what they're doing and we have to ask if we're alright."

"This is the first film I'm not allowed to discuss... I've made it, man! I'm loving it!"

"Harry Potter has a history. They've read the book and they've got kids to answer to, these people. That's a different kettle of fish, it's like being called up. You get a phone call, and they'll say, 'Listen, the Queen's a bit lonely tonight. Fancy popping over in your favorite underwear?'

It's like the call-up, and it's so funny. You get on set and you see all these actors who you've either admired from afar or more often than not, actors you've worked with before, all sitting there, dressed up as wizards, having wand-offs, and then [complaining] about other actors who didn't get the call-up. It's just such a surreal situation to be in. I was really genuinely proud to have been invited to be part of that whole machine."

“It was four days of concentrated, joyous and frightening work. Daniel Radcliffe, Emma Watson and Rupert Grint, they’ve been doing these roles their whole lives. They know who they are and what they’re playing. I come in, and I have no idea who or how or what. I mean, I’m supposed to be Michael Gambon, Dumbledore’s younger brother. But he’s 190 and I’m probably 156 or so. And I’m much grumpier than him. But it’s such a great honor to be asked, as so many of my peers have asked, to be a part of that world, if only briefly.

“You work for years, decades, and you might be recognized here and there. But people find out ‘YOU were in Harry Potter!’ and the whole conversation changes. ‘REALLY?’ I was a little slow to realize what a big deal the thing is, but I felt that, personally, almost the moment we wrapped.”