Jennifer Aniston got John Mayer warmed up for his Grammys performance at her 40th birthday party Saturday night.

Jennifer Aniston got John Mayer warmed up for his Grammys performance at her 40th birthday party Saturday night.

Julia Roberts, who was well-known to be the “Pretty Woman” star, celebrated her 41st birthday (which is actually on the 28th) a day early with a star-studded party in San Francisco.