The two singers have been keeping their romantic relationship pretty under wraps since July – but last night "KatJo" (eh, too soon for nicknames?) made their very first red carpet appearance together!

Katy Perry, 28, and John Mayer, 35, got in the Christmas spirit as they attended a Broadway showing of "A Christmas Story: The Musical" in New York on Wednesday.

The couple posed for pictures with the cast and composers … and it was pretty obvious that John couldn’t keep his eyes off the "Fireworks" singer!

Katy looked holiday-chic wearing a Dolce & Gabbana winter sweater – she styled her signature black locks straight and finished her look with chunky jeweled earrings.

John matched his "Part of Me" lady in a brown plaid blazer, matching scarf, and tan slacks – think it was intentional?

Even though we’re not fans of Mayer’s dating record … they do make one good-looking couple! See all the pictures from their Broadway night in the gallery above!

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