And Katy Perry was one of them. According to the video and Radar, they were at Dimples Supper Club in Burbank California for Shannon Woodward's birthday party. Later they headed to the Renaissance hotel in Hollywood to continue the party.
The story is from Radar Online, so take it as you like... Not the most reliable source at all.
As far as I know Katy is with Russell Brand , yes they are in love. There are even talks of a marriage proposal this month.
If you want to watch the stalkerific vids here and here. All I see are friends having fun. Shannon Woodward's boyfriend is Britpacker, Andrew Garfield, who is also Rob's friend. Also, towards the end of the second vid you can see Russell and Katy holding hands. Russell is the one wearing a beanie with long hair.
Via RP Life