There are a couple of films that I've done, where I've had to get on a horse and wear a pair of tights, so that helped. But, nothing could have prepared me for the fun of wielding magic like Merlin does, especially in the perverted mind of Chris Chibnall.
It's all about human condition, ultimately. That's what you're looking at. You're also looking to have some fun, as well, because that also translates. Maybe wearing tights once in awhile helped. Getting up on a horse a couple of times before might have helped.