we know each other
I think we know each other.
Мы знакомы с ним больше двадцати лет.
We've known him for more than twenty years.
Ну, ну, мы знакомы очень давно.
Well, well, we've known each other for a very long time.
— Плата за страх (1953)
We have known each other since childhood.