So Brad Pitt Was at Jennifer Aniston's 50th Birthday Party Last Night

Jennifer Aniston is turning 50 years old on Monday, so naturally she hosted a birthday bash last night in Los Angeles.

Her party was filled with celebs including Katy Perry, Orlando Bloom, Reese Witherspoon, Laura Dern, Gwyneth Paltrow, John Mayer, Robert Downey Jr., Kate Hudson, Demi Moore, George and Amal Clooney, Courteney Cox, Barbra Streisand, and Lisa Kudrow.

But perhaps the most unexpected guest was none other than her ex husband Brad Pitt, who People reports made a "casual" entrance into the celebration.

Obviously, it makes sense that Brad would be there—after all, him and Jen were married for years, and just because two people get divorced or have a rocky breakup doesn't mean that they have to be mortal enemies for the rest of time.

That said, it is a little surprising to see them being so friendly, especially since it's not exactly in their general public narrative...what do you think of all this?