Movie siblings can make or break the believability of a feature film. Cast two actors who can convincingly play family members, and you're in the clear; cast two actors who look nothing alike, and you're in trouble.
Thankfully, "The Five-Year Engagement" falls in the former category. In the film, actresses Emily Blunt and Alison Brie play sisters, and not only do they look alike, but they sound alike too. (This is quite a feat since Blunt is British and Brie is not.)
"I had a great vocal coach here in LA for a few weeks, but when I got out there, Emily became my unofficial vocal coach," Brie said last year to The Insider. "It was more important that we sound alike than me studying a super proper British accent." Mission accomplished, Alison!
In honor of the success of "Five-Year Engagement," HuffPost Entertainment has compiled ten other great sibling pairings from the big screen. Leave your own favorites in the comments below!