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Jennifer Lawrence cozied up to one of the stars of her favorite show Saturday night in West Hollywood ... and TOTALLY fangirl'ed out.

The "Hunger Games" star hit up Pump with her friends and we're told Lisa Vanderpump hooked JLaw up with the best seat in the house ... and then snapped a pic with the group.

It's interesting ... When the actress walked in no one noticed her and she was seated in the less desirable outside area facing Santa Monica Blvd. When Vanderpump realized what was up, Jennifer was moved to Lisa's personal table.

Jennifer was drinking Pump-tinis and Lisa's Sangria.

Lawrence has confessed she LOVES reality TV ... and the Instagram video makes it clear ... in her head Vanderpump Rules.