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Pete Wentz and new girlfriend Meagan Camper couldn't stop smiling at each other Saturday night!

The couple hit The Roosevelt hotel and nightclub in Hollywood, then walked down the street to grab some late-night pizza. It's always good to eat up after a night of partying!

It's nice to see Wentz, 32, happy again after his split from wifey Ashlee Simpson in February! Meagan wore Pete's hat, and inside the restaurant they fed each other -- watch in our video below!