Pop superstar Katy Perry made a special appearance on Ellen DeGeneres' birthday show today (January 25) and dressed in an unusual disguise.

The show was to celebrate the well-loved host's 55th birthday, which is actually tomorrow, and Perry played the part of a male game show presenter complete with a cropped brown wig.

"I asked for the Anne Hathaway, obviously," she joked of the hairpiece. "I am actually a second cousin to Bob Barker."

Perry then called two audience members down to the stairs for the chance to win a prize and told them: "Don't worry, ladies. You won't be winning a kitchenette set."

Tweeting to the 'Teenage Dream' singer earlier this afternoon about her outfit and temporary sex change, DeGeneres wrote: "You look fantastic."

Watch the entertaining segment in full below: