Katy has had more than one memorable Met Gala look, but her 2017 outfit for Rei Kawakubo/Comme des Garcons: Art of the In-Between was truly something. As cochair of the event, she had to make a statement, and this Maison Margiela dress was just that.
What to wear: The most over-the-top red dress you can find, with a long red veil. Bend some pipe cleaners or wire to spell out "Witness" to wear as a headpiece.