Other guests at the party were said to include another of Brad's former flames, actress Gwyneth Paltrow, as well as Jennifer's former boyfriend John Mayer, and the singer's ex-girlfriend Katy Perry, who arrived by motorcycle with her partner Orlando Bloom.
The event marked a milestone birthday for Jennifer, prompting her to celebrate with all of the people who have had an impact on her life, People magazine reports.
"Brad, for long, was a very important part of Jen's life".
The former Friends star, who turns 50 today, rung in her half century a little early with a star-studded bash at upscale Sunset Tower on Sunset Boulevard on Saturday, February 9.
It is believed she ducked out of her birthday bash at around 1am in the morning.
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"They hugged and chatted for a bit, but Jen was busy making sure all of her other guests had an incredible time", the source added. Kate Hudson wrote on Sunday, alongside a series of shots of herself, Aniston, and Paltrow.
"Love these ladies Celebrated this beauty last night ✨Happy Bday JA!"
Composite image of Jennifer Aniston (L) and Brad Pitt.
She said: "I don't feel a void". I really don't. My marriages, they've been very successful, in [my] personal opinion. And when they came to an end, it was a choice that was made because we chose to be happy, and sometimes happiness doesn't exist within that arrangement anymore.
Jennifer, who split from Justin Theroux in 2017 after two years of marriage, recently opened up about her past relationships, and insisted she would never stay in a troubled marriage for fear of being alone. Fear of being alone.
Speaking to People, an insider revealed that Aniston allegedly "debated" whether or not to invite him, but in the end was happy that she did.