Katy Perry (left) and Allison Williams
02/08/2013 AT 12:00 PM EST
The Grammy Awards
will be a girls night out on Sunday for nominee Katy Perry
, who has invited a surprising plus-one.
Perry, 28, who is currently in a relationship
with John Mayer
, 35, plans to take gal pal and Girls
star Allison Williams
. Mayer, however, is expected to present at Sunday's show.
The chicks-only night on the town was confirmed by Williams to host Anderson Cooper
when she appeared on a Thursday episode of his Anderson Live
"I am going to the Grammys and Katy Perry is my date," Williams said. "She's the hottest date. She's a friend of mine and she's nominated, as she should be. I can't wait to go."
The pop star
and Williams reportedly became pals through their men
. Williams dates College Humor founder Ricky Van Veen, and the couples have double-dated, E! Online reports.
Perry, who is currently in the studio working on new music, is nominated for Best Pop Solo Performance for "Wide Awake."