There are plenty of wild behind-the-scenes stories from the Harry Potter franchise, but Daniel Radcliffe’s latest recollection about filming Harry Potter and the Goblet of Fire might be one of the more humbling ones. While the Triwizard Tournament’s underwater task looks seamless and magical onscreen, the reality of shooting Harry’s dive into the Black Lake was far more intense — and at one point, genuinely panicked. And the moment prompted a pretty brutal response from the stunt coordinator.
In a clip from Hot Ones, shared on the show’s official Instagram, Daniel Radcliffe was promoting his 2026 TV schedule comedy Fall and Rise of Reggie Dinkins when he was asked about the underwater sequence. The host wanted to know if he really spent nearly 42 hours submerged while filming and whether he ever used a drowning signal or had any close calls. Radcliffe’s answer was refreshingly honest. He admitted that during training for the scene, there was one brief but chaotic moment that led to a blunt response from his stunt coordinator. He explained:
I only once didn’t… there was a time when we were training for it where I, we were doing, like, mask-clearing exercises, a very basic thing for learning to dive. And you, you take a deep breath and you take the regulator out, and then you, when you put it back in, you’ve got to keep that breath, to blow the air out. And I remember, I took the thing out once. And I was like, ‘Didn’t breathe. Don’t have any breath to clear this one.’ … I put it back in and… yeah, I was like, [franticly panics] like, go, which is get me out of here. That’s my drowning signal, and they, and I got up, and the stunt coordinator just looked at me in the only way he could. He’s a lovely man called Greg Powell, he just looked at me and went, ‘Well, you won’t make that mistake again.’
There’s something so British about that response. The Horns star admitted the underwater shoot was no small undertaking. While the 42-hour figure has been widely cited, what’s even more staggering is how little usable footage they were actually getting after days of intense stunt work. He continued:
We filmed for six weeks… and I think we.. I heard it quoted we averaged 5 seconds of usable footage per day. That was one of the things you gotta, ‘yeah I’ll never… never do something like this again.’
Rewatching the Black Lake scene now hits differently with that context. The serene bubbles, the eerie quiet, the slow drift of hair in the water, all of it came from weeks of physically taxing work. It wasn’t simply CGI wizardry. For the beloved Potter actor, trained extensively to hold his breath and perform underwater sequences with minimal cuts, which makes the final result even more impressive.
What really seals the story, though, is Greg Powell's perfectly timed line. It was blunt, maybe even a little merciless, but also reassuring in its simplicity. Radcliffe clearly took it to heart. He powered through one of the franchise’s most technically challenging shoots and delivered a sequence that still stands out decades later. And somehow, it’s comforting to know that even The Boy Who Lived had a split-second of panic — and a stunt coordinator ready with a no-nonsense reality check.
If this behind-the-scenes story has you wanting to revisit the Wizarding World, and the Black Lake challenge specifically, that's easy to do. The Harry Potter films are available in 4K, Blu-ray, and DVD, and can also be streamed digitally on Peacock and via an HBO Max subscription.
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