The event is being held by Sean Penn with Core Response to raise money for the charity, with Jimmy Kimmel, Morgan Freeman, Shia LaBeouf, Matthew McConaughey and Julia Roberts also taking part.
It will be the first time Brad and Jennifer's have worked together since the Fight Club actor guest-starred in Jen's hit sitcom Friends back in 2001 while the couple were married. In the episode, he hilariously played Monica and Ross Geller's old school friend Will Colbert who *hated* Rachel Green. Brad and Jen also practically broke the Internet when they were photographed together backstage at the SAG awards back in January.
According to a press release, the live-streamed event will be an "unrehearsed, anything-goes table read" - so here's hoping we get to hear some flirty banter between the exes.
Following their respective wins - Brad for his Best Supporting Actor award for his role in Once Upon a Time in Hollywood and Jen for her Female Actor in a Drama Series for The Morning Show - they shared a sweet moment to congratulate each other backstage.
If you'd like to watch them together anyway, you can donate and watch the charity livestream of Fast Times at Ridgemont High on Facebook here at 1am BST on August 22nd.