Credit: Kevin Winter/Getty Images for DGA

Pre-birthday bash at the Chateau!

On Friday night, one day before her 43rd birthday, Jennifer Aniston was already in a festive mood.

The Horrible Bosses actress turned up at Chateau Marmont in West Hollywood with love Justin Theroux and another male pal -- grabbing her favorite spot on the back patio.

She and her man, 40, wore both clad in black with rocker-style leather jackets. "She looked great!" one onlooker tells Us, adding that she was "in a great mood...smiling and glowing."

Arriving past nine, Aniston, Theroux and their pal drank wine as they chatted (and laughed!) for an hour and a half. Dating for nearly a year, the duo looked more in love than ever, according to the Chateau onlooker. "They touched each other alot! He had his hands in her hair at one point."

They left before 11pm, hand-in-hand. No word yet on what Aniston and Theroux have planned for her big birthday weekend.