You will need 2 people or a fake person
In order to do this you will first need to unlock the crew looks for two characters from the same crew. You unlock new outfits by earning stars and raising levels, with the crew looks starting to unlock around level 15. Once you have both members of a crew (ie Angel and Miss Aubrey or Emilia and Bodie) with their crew looks unlocked, do a two player performance with each character in their crew look and the achievement will unlock.
See "Walk-In Closet" for more details