Henry Cavill improvised the unhingedness in the Ministry of Ungentlemanly Warfare.

The Witcher star added a little bit of his own touch in one of the scenes in director Guy Ritchie‘s movie.

In several mature scenes, Henry Cavill‘s character Major Gus March-Phillipps wholesale kills Nazis while sticking his tongue out in a nutty, mad grin, catching viewers’ attention in the action film’s first trailer.

“It was a co-improvisation between Guy and myself,” Cavill told Variety at the film’s New York premiere Monday.

“Guy said, ‘I want you to have more fun with it. Stick your tongue out or something.’ And so we did and it stuck, as featured quite well in the trailer. That was the first moment where we decided Gus was going to be slightly unhinged in these moments, and that makes it more fun.”

Writer Arash Amel, who took inspiration from the 2014 book Churchill’s Secret Warriors: The Explosive True Story of the Special Forces Desperadoes of WWII by author Damien Lewis, admitted that the movie’s team took “creative liberties, but everything is rooted in truth.”

“It was totally in the essence of Gus March-Phillipps to behave exactly in that way,” Amel said of Cavill’s tongue-wagging scene.

“He was the guy who blew up a bridge in Norway when he was told not to by British high command and almost got court marshalled. So for him, he lived to kill Nazis in the same way Alan Ritchson’s character Anders Lassen lived to kills Nazis. These guys were built from a different breed. He didn’t stick his tongue out, but who knows maybe he did? He embodied Gus from start to finish.”