Perez Gathers Frenemys to Celebrate Success of His New Book.

Millions of Milkshakes became one of the most star studded places to be in Hollywood this weekend, when Perez Hilton, Kourtney Khloe and Kim Kardashian, and Spencer and Heidi Pratt all (coincidentally) showed up at the same time.

Celebrating the success of his new book, Perez conveniently had copies of Red Carpet Suicide for all of his pals, and they all took time to flip through the pages and pose for some photos.

Then they each headed behind the counter to help the staff make up their own milkshakes, check out the way Heidi Montag sucks that thing down right out of the blender.  Very lady like.

Check out the mega photo overload below!