Sam grew up in an artistic family. He told Interview magazine that his dad's a sculptor and a painter and his mum ran an art gallery, while his little brother trained as an illustrator. He did "a little bit of painting" himself but then went down the performing arts route.
His parents were totally supportive of his going to drama school to become an actor and had the attitude that he should do what he's good at and what makes him happy. Very sadly, Sam's mum passed away in November 2018.