This movie is about a girl who has to go meet her significant others parents (I believe they are either married or engaged). Anyways on the day they are supposed to go meet them the husband gets an allergic reaction to something and can't go so he suggests that she take his twin brother. Although they look identical they are very different. He is super nerdy and awkward, and his twin is a smooth ladies man who is a bit of a jerk. Anyways she agrees and goes to meet his parents with his twin and ends up falling in love with him.
That's basically all I can remember. Any help would be appreciated!!