The actor, 24, joined the cast of the series (returning to BBC3 in February) about the titular bomb disposal unit in Helmand Province at Christmas, and found chippy, newly arrived Yorkshireman Corporal Gordon House, nicknamed Tower Block, engaged in a class war with Captain Nick Medhurst, played by Oliver Chris.
Although a tour of duty in Helmand might seem a far cry from life at Hogwarts School of Witchcraft and Wizardry, Lewis, who spent 10 years working on the Harry Potter franchise, says the two worlds aren’t as different as you might think.
“You’re all together, sleeping in the same quarters, and you’re around each other all the time,” he says, adding that he considered joining the forces himself when he became disenchanted with life as a child actor.
“I actually did think about it when I was about 14,” Lewis reveals. “I’d been doing Harry Potter for a few years, and I was in a bit of a rebellious phase thinking: ‘I don’t want to do this any more – I’ll join the army’.
“Then I got a bit older, started to enjoy the acting a lot more, and stayed on that path. I’m so glad I did, because I’d have been the worst soldier of all time.”