Don't tell Jennifer Aniston to forgive and forget! The angry actress branded her former "Friends" co-star Courteney Cox a traitor after Courteney made nice with her ex Brad Pitt and her arch nemesis Angelina Jolie.

At the Jan. 15 Golden Globes, Courteney and husband David Arquette bumped into Brad and Angelina during a break in the awards show.

"Jen is insulted that Courteney took the initiative and went straight up to Brad when he was there with Angelina," disclosed an insider.

"In Jen's mind, Courteney could have easily avoided them. It's like Courteney went out of her way to be super nice to Brad."

The "Babel" star gave Courteney a bear hug and cooed, "Hello, sweetheart. It is so great to see you."

And he introduced Arquette and Cox to Angelina as "dear friends."

Courteney and David briefly chatted with Brad about their kids, and Angelina stood awkwardly a few feet away — before finally leading Brad away.

Get more details — and Jen's reaction — in this week's ENQUIRER!