Jeff Bezos, Lauren Sanchez & More A-Listers Party at Pre-Oscars Bash

Hollywood's elite are warming up for the Oscars with pre-parties all over the city of Los Angeles ... with the best of the biz out to play ahead of the glitz and glam to come later tonight.

One of them was a massive shindig that went down Saturday night at a private mansion in Beverly Hills and major A-listers were on hand to celebrate including Jeff Bezos and Lauren Sanchez, Leo DiCaprio, Sean Penn, Mick Jagger, Pamela Anderson, Goldie Hawn, Cara Delevingne, John Mayer, Jon Hamm and Michael Keaton.

Everyone wanted in on the big party ... autograph seekers and fans were seen outside the party trying to get pics with all of the stars as they came and went from the party for Hollywood's biggest night.

Also rubbing shoulders and mingling at the bash was Jenna Ortega, Joey King, Miles Teller, and Brandon Lee.