Katy Perry & Adam Lambert: 'Britney: Piece of Me' Supporters!

Katy Perry shorts a “Nu Frenz” shirt while arriving at the grand opening of Britney Spears‘ two-year residency Britney: Piece of Me held at Planet Hollywood Resort & Casino on Friday (December 27) in Las Vegas.

The “Unconditionally” singer was joined on the red carpet by Adam Lambert, who was dapper in a bold suit.

PHOTOS: Check out the latest pics of Katy Perry

“Soy excited to see @britneyspears baby bottle pop it off tonight at her grand opening @phvegas! We are coming in full lewks to support!” Katy tweeted earlier in the day.

In case you missed it, check out Katy and her boyfriend John Mayer showing chemistry in the new music video for their song “Who You Love.”

10+ pictures inside of Katy Perry and Adam Lambert attending Britney: Piece of Me…