Jennifer Aniston, Brad Pitt
Jennifer Aniston and Brad Pitt are pictured attending the 56th Annual Primetime Emmy Awards on Sept. 19, 2004, in Los Angeles. Getty Images/Kevin Winter

Brad Pitt and Jennifer Aniston's marriage didn't work out for a reason, according to the actor.

While Pitt is now friends with his first ex-wife, with whom he was married for five years before they divorced in 2005, the actor apparently felt that their marriage may have been a pretense on each of their part. During an interview with Parade back in September 2011, Pitt explained that he had been trying but failing to live "an interesting life" at the time.

“I spent the ‘90s trying to hide out, trying to duck the full celebrity cacophony. I started to get sick of myself sitting on a couch, holding a joint, hiding out. It started feeling pathetic. It became very clear to me that I was intent on trying to find a movie about an interesting life, but I wasn’t living an interesting life myself,” he admitted.

“I think that my marriage [to actress Jennifer Aniston] had something to do with it. Trying to pretend the marriage was something that it wasn’t,” the dad-of-six explained.

But while they didn't work out as a couple, Aniston and Pitt have reportedly now become friends. The "Fury" actor made an appearance at Aniston's 50th birthday party in West Hollywood's Sunset Tower because he "wanted to support" her during this milestone, E! News reported.

An insider told Entertainment Tonight that Aniston and Pitt "have remained friends and have spoken with each other quite a few times since they both became single. They are friends and have supported each other through some tough times. They've come so far since their marriage and plan to stay friends for life."

The same source added that the two exes have "no hard feelings" toward each other.

As for why Pitt attended her birthday bash secretly and left before it ended, the source explained that Aniston and her ex-husband wanted to avoid rumors about them rekindling their romance.

Following their divorce, Pitt tied the knot with Angelina Jolie in 2014, while Aniston married Justin Theroux in 2015. However, the "Mr. & Mrs. Smith" co-stars' marriage ended in 2016 after Jolie filed for divorce. Aniston and the "Leftovers" star also announced their split last year.

Pitt and Jolie recently regained their "single" status despite not having finalized their divorce. The two settled the custody agreement for their six children, Maddox, 17, Pax, 15, Zahara, 14, Shiloh, 12, and twins Knox and Vivienne, 10, late last year after a two-year battle.