Talk about an A-list bash!

Katy Perry threw boyfriend Orlando Bloom a surprise party in Palm Springs for his 40th birthday over the weekend, and some of the famous guests included Jen Aniston and husband Justin Theroux. We didn't know the "Roar" songstress and the actress were friends, and we're especially shocked because they both dated John Mayer!

The Leftovers star was caught in a rare moment without his leather jacket, as he posed shirtless with the Pirates of the Caribbean actor and some other dudes.

Looks like a wild time was had by all!