Some roles require actors to learn martial arts.

Others demand that they gain weight.

“It was a very strange experience,” theStranger Thingsstar tells EW.

Violent Night David Harbour

David Harbour in ‘Violent Night’.Allen Fraser/Universal Pictures

“I put on about 70 pounds,” explains the actor.

“I was up in Winnipeg, I just needed the padding.

I got real big for it and then I was also doing jiu-jitsu for months beforehand training for it.

The look that I wanted him to have was: big old strong Santa Claus.

You’ll see in the movie, I got big in all ways.

It was very weird.

My movement was somewhat restricted because I had these big old love handles.

So we were sort of like big old walruses.”

This all sounds like the world’s tastiest fitness program.

“Yeah, Jane Fonda, better watch your back.”

“I think there’s a whole industry there for me.”

Violent Nightis directed by Tommy Wirkola and co-stars John Leguizamo and Beverly D’Angelo.

The film hits theaters Dec. 2.

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