Angelina Jolie fighting with tough emotions after Brad Pitt attends Jennifer Aniston's birthday party

Angelina Jolie was allegedly shocked after Brad Pitt attended Jennifer Aniston's 50th birthday party recently. The 55-year-old actor arrived at the event, which took place at the Sunset Tower Hotel in Los Angeles.

According to a report in Hollywood Life, the mother-of-six could not accept the fact that the former couple is in good terms now. A source said: "Angelina is shocked that Brad went to Jennifer's birthday party. She was aware they were back in touch but didn't realize they'd gotten that close again."

"It brings up a lot of tough emotions for Angelina but she's not dwelling on it. As hard as it is for her to know that Brad and Jennifer are hanging out, she knows there's nothing she can do about it and she is choosing not to focus her energy there," the insider added.

The Cake star and Brad were married from 2000 to 2005. That marriage ended in part because he was rumored to have left for Jolie, who he met and fell in love with on the set of their film, Mr. and Mrs. Smith.

In September 2005, in Jennifer's first post-divorce interview with Vanity Fair, she shared her true feelings about Brad moving on so quickly with Jolie. She said: "I would be a robot if I said I didn't feel moments of anger, of hurt, of embarrassment."

However, the former Friends actress admitted she is completely at peace with her split from Brad, 10 years after their separation. She told CBS News in January 2015: "I don't find it painful, though. I think it's a narrative that follows you because it's an interesting headline. It's more of a media-driven topic."

At that time, Jennifer even revealed that they still talk – although not on a regular basis. She shared: "We've exchanged good wishes and all that sort of stuff to each other. But it's not a constant thing."