Aniston and Pitt first met in 1998 and married in 2000 when they instantly became a Hollywood power couple.
Indeed, Angelina Jolie's estranged husband and the father of her children made jaws dropped on the floor where he showed up at the Sunset Tower Hotel.
Aniston was surrounded by her close gal-pals, including jewelry designer Jennifer Meyer, who shared snaps with Aniston surrounded by friends including Sara Foster and Jason Bateman's wife, Amanda Anka.
Much has changed for Aniston since she burst on the Must-See TV scene in 1994. "But the friendship is shifting and changing, you know, so that part is something that we're both very proud of". She debated back and forth with friends if she should invite him.
Would you believe us if we told you February 7, 2019 marks Jennifer Aniston's 50th birthday?
Gwyneth Paltrow, who was engaged to Pitt until 1997, was also spotted at the bash, as well as Aniston's former castmates Courteney Cox, Lisa Kudrow and Cox's ex-husband, David Arquette.
Because of that fact, the "Friends" star threw a party for her 50th birthday over the weekend and she invited a few of her celebrity friends.
In an interview for the January issue of Elle magazine, Aniston also spoke on their 2018 breakup.
"I don't feel a void". Not only that, but there have been rumors of an Aniston/Pitt reunion for years - but in the end, it always turns out the two have just remained great friends.
'My marriages, they've been very successful, in personal opinion. The decision "was mutual and lovingly made at the end of past year", Aniston's longtime publicist, Stephen Huvane, said at the time. 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'.