The singer requested that all her guests dressed up in white for the Charlie And The Chocolate Factory-themed party at The Beach On Sunset in West Hollywood, which was turned into Willy Wonka's factory.

Guests included boyfriend Russell Brand, Taylor Swift, Zachery Levi, Joel Moore and, er, some Oompa Loompas.

According to a source, Russell and Katy were all over each other proving their publicity stunt relationship is still going strong.

They said:

"They were totally loved up. Katy was having a ball and Russell was catering to her every whim. At one point he was down on his knees bowing and offering her a huge swirly lollipop. She grabbed it from his hands and pretended to knight him with it."

What, in front of everyone?? We thought they'd save that until all the guests had left...

Happy birthday, Katy!