Popsugar Entertainment Halloween Mary-Kate and Ashley Olsen Halloween Costumes 14 Mary-Kate and Ashley Costume Ideas That Are Double the Trouble For Halloween October 28, 2017 by Kelsie Gibson View On One Page Photo 4 of 15 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 4 Maddie and Abby, Our Lips Are Sealed What to wear: Go full on go-go girl, complete with white boots. Differentiate your looks by having one of you wear a headband. How to act: Like you are incapable of keeping a secret. Previous Next Start Slideshow HalloweenAshley OlsenMary-Kate OlsenNostalgiaHalloween CostumesPop Culture Halloween CostumesMoviesHalloween Costumes For Women