Must be the go to color!

Katy Perry was in town for her Prismatic Tour and performed in front of a packed house at the Staples Center, with many fans and celebs in attendance!

Ashley Greene and Julianne Hough were just a few of the famous people who showed the pop star some support but was there a memo to wear all black?

Both ladies rocked it well for the concert, but we're sure they have more colorful ensembles at their disposal!