Alexander Vlahos has revealed how getting his hair shaved off for Privates was "a shock".
The Merlin actor, who plays trainee soldier Private Keenan in the BBC One drama, had to get his head shaved - while being filmed on camera.
"It was part of the contract so we knew our hair was going to be gone by the end of the day, but it doesn't prepare you for the actual brutality of what happens," he admitted.
"There was an extra clipping our hair so he wasn't even a barber, and you're on camera and they only have one shot at it. It was one take and they had to get it right because it wasn't like my hair could grow back again."
The 24-year-old, who previously played Mordred on Merlin, added: "I was one of the boys with the longest hair, so it was a bit of a shock. But because I was being filmed, I couldn't mourn my hair. If I was at a hairdressers, I would probably well up, but you can't when you're in character."
Alex reckons that he would struggle if he had to partake in National Service.
"My character Keenan is a pacifist and is anti-military. He's outspoken and doesn't do well with authority. If I had to sign up, I would struggle to lose my individuality," he said.
Privates is shown every day on BBC One from January 7.