Popsugar Entertainment Halloween 40 Best Sister Costume Ideas For Halloween 2023 40 Best Sister Costume Ideas For Halloween October 6, 2023 by Maggie Panos First Published: October 1, 2015 View On One Page Photo 25 of 41 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 25 Sister Halloween Costumes: Anne and Mary Boleyn From "The Other Boleyn Girl" What to wear: This is the 16th century, so you'll need some voluminous dresses with headpieces to match. How to act: Mary is young and innocent; Anne is ambitious and selfish. Previous Next Start Slideshow HalloweenHalloween CostumesPop Culture Halloween CostumesTVMovies