But before accepting his (rather surprising) invitation to the big bash, Brad had one very important question to ask his ex-wife.
According to reports from US Weekly the Benjamin Button actor has spent much time reflecting on the way his five-year union ended to the former Friends star, and "asked for Jen's forgiveness a long time ago".
The outlet further claims the 55-year-old "wishes he'd handled the end of their marriage in a more thoughtful manner".
Jennifer is said to have forgiven her ex, despite the nature of their split which ultimately ended in divorce in October 2005.
Less than a month after finalising their separation, Brad moved on with his Mr and Mrs Smith co-star Angelina Jolie.
Brad infamously fell for Angelina while still married to Jen on the set of the 2004 box office smash , sparking over a decade of speculation and rumours about all three parties.
But it seems bygones truly are bygones - at least for Brad and Jen - with the Inglorious Bastards actor reportedly giving his former flame "a card and a hug" at her half century celebration.
A inside source further revealed to In Touch magazine that after the gathering the friendly exes met up afterwards where they "chatted and didn't look awkward at all".
The source told In Touch that at one point during the night the old flames enjoyed a secret kiss: "What people don't know is that they got together after the party ended."