Plenty of celebrity siblings have played opposite one another in film and TV. Maggie Gyllenhaal
and Jake Gyllenhaal
famously played a brother/sister duo in the cult hit Donnie Darko, while Tia and Tamera Mowry starred as twins in the '90s sitcom Sister Sister. But casting on-screen siblings who aren’t related can be tricky since simply looking alike doesn’t necessarily cut it if the actors don’t have the right accent, rapport, or mannerisms.
Related: 15 Best Brother And Sister Duos In Film & TV History
That said, there are tons of on-screen siblings who aren’t related in real life - though from their looks and their behavior to their relatable sibling squabbles, they definitely could be. These on-screen sibling duos could all pass as real-life relatives.