Katy Perry and John Mayer can't keep their hands off each other!

After enjoying a meal at West Hollywood Italian eatery Osteria Mozza on Friday, Jan. 4, the couple exited the restaurant hand-in-hand, with Mayer leading his lady protectively down the street. Perry, clad in a forest-green floral dress and carrying a studded leather jacket, held tight to her on-again boyfriend as they made their way back to their car.

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"They are seriously in love and exclusive," a friend told Us Weekly recently of the pair, who celebrated Christmas with the "Wide Awake" singer's parents in Santa Barbara, Calif.

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Indeed, aside from their brief split in August, the two have been nearly inseparable since first hooking up in June 2011. Last month, they bonded with Mayer's dad, Richard, at a performance of A Christmas Story on Broadway, where Perry introduced the musician to the cast as her "boyfriend."

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"John is surprised at just how cool and smart she is," a pal of the "Born and Raised" songwriter told Us.

Another friend added: "John has proved he's matured and learned from his mistakes...Katy is blown away."

This article originally appeared on Usmagazine.com: Katy Perry, John Mayer Hold Hands After Romantic Dinner Date: Picture