Bachelorette (2012)

Directed by Leslye Headland, Bachelorette stars Kirsten Dunst, Isla Fisher and Lizzy Caplan as three former friends invited to be bridesmaids at a wedding for a woman they once mocked in high school. Based on Headland’s play Bachelorette, the film follows a chaotic night of drugs, insults, jealousy and bad decisions before the ceremony. Rebel Wilson co-stars in this dark wedding comedy about friendship, resentment and self-destructive party behaviour.

Från IMDB:
Three friends are asked to be bridesmaids at a wedding of a woman they used to ridicule back in high school.