Now she has decided to share with the world her utter contempt for Angelina Jolie.
In the forthcoming issue of U.S. Vogue, Miss Aniston, 39, gives a searing condemnation of her notorious nemesis.
In an outburst that will lift the lid on their four-year feud, Miss Aniston icily told the publication: 'What Angelina did was very uncool'.
The brief yet explosive comment marks the first occasion that the former Friends star has spoken out publicly about her love rival.
It comes just a fortnight after Miss Jolie, 33, revealed that she and Pitt had 'fell in love' during the making of Mr and Mrs Smith in 2004, despite previously claiming their romance only started after filming.
A source said: 'This interview shows that Jennifer is no longer afraid of Angelina,' adding: 'It's hugely significant.'
In the magazine's December issue, Miss Aniston is said by industry insiders to have given her most candid interview yet, offering countless details about her new Beverly Hills estate, her unusual relationship with her parents, and intimate secrets about her romantic life.
Enlarge Star of the film Brad Pitt and his wife Jennifer Aniston arrive for the premiere of Troy, at the Palais de Festival during the 57th Cannes Film Festival in France. Thursday 13 May 2004
'She's never been this honest or brave in an interview before,' said the source, who has seen the completed, lengthy package, due on sale in the U.S. in a few days.
The source added: 'This certainly raises the bar on celebrity profiles. Jennifer opens up about her sex life, her career, and her feelings about life after her divorce.
'She must have had a lot on her mind, because she lets go on everything.'
MailOnline has learned that Miss Aniston's new Vogue appearance features the actress posing in erotic designer swimsuits and bearing her toned body on the sun-kissed beaches of Malibu.
'This thoroughly re-establishes her credibility as a sex symbol,' the source went on, adding: 'Her body has never looked tighter or more fit.'
But her thoughts on Miss Jolie, who famously started a family with Pitt, will indubitably attract the most attention.
The cover prominently blares: 'What Angelina did was very uncool', which appears to be a direct jab at Miss Jolie's 2007 interview with the same magazine.
During that interview, Miss Jolie condescendingly offered to meet with Miss Aniston to hash things out and resolve their feud.
'If she wanted to [meet] then I would be open to it,' she famously told the publication.
Meanwhile Miss Jolie, currently promoting a new film, revealed yesterday that she and Pitt plan to have more children together.
Speaking in Hollywood alongside Dustin Hoffman, she told reporters: 'I have a great partner. He's the best daddy and we have fun, so whenever it gets hard we can just look at each other and find a way to laugh about and just appreciate that they're only little once, and we should enjoy every minute.
On adding to their brood, she said: 'Anything could happen. We're open to anything, we love kids and we're having a great time. It's chaos in our house but it's so much fun. We'll definitely have more.'