A bit of an ‘odd duck’
There's a wonderful phrase in English that refers to 'the odd duck'. Popular in the 1940s and 50s, it was often used to discuss a person, like cousin Robert who wears those loud shirts and spends all his time with his friend, Jeremy. Or for great aunt Amy who only wears tartan and plans on leaving her entire fortune to her cat. You'd say, “She's a bit of an odd duck, eh”.