Jennifer Aniston's 40th Birthday Bash

Jennifer Aniston is throwing herself a star-studded 40th birthday party at her new Beverly Hills home tonight, and only RadarOnline.com has exclusive video of tents going up at her place as she prepares for the blow-out bash.

Tonight's party is pure A-list. Guests include Jennifer's boyfriend John Mayer, BFF Courteney Cox and husband David Arquette and singer Sheryl Crow.

Jennifer actually turns the big "4-0" on February 11th, but the buzz around Hollywood is that Jen is planning an early birthday bash because John wants to whisk her away for a romantic getaway for her actual birthday. Rumors have been flying lately that John will propose on Jen's big day and has already splurged on a custom-made engagement ring for her.

We'll have to wait to see if that's true, but we do know Jen is looking forward to marking this milestone birthday and isn't scared of getting older. Jen says, "Everyone has been asking me if I worry about being nearly 40, but no, not really. These days I'm a lot more serene and I'm ready to embrace a new decade. It almost feels like a badge of honor in a weird way."

Happy Birthday to our favorite friend!