Kristen Stewart spotted partying it up at Katy Perry’s birthday bash last night. According to Hollywood Life and their sources, Twilight Saga hottie Kristen Stewart was spotted back out to make her partying rounds at Katy Perry’s big birthday bash this past Friday night. Katy also happens to be good friends with K-Stew’s main man Robert Pattinson,so this was no coincidence.

They say, Kristen attended the event with Rob’s friend Marcus Foster,and it took place at The Magic Castle on October 19th. Sources for JustJared.com claim, Kristen ” looked happy and was surrounded by her friends the whole time.”

Katy celebrated her birthday with a costume party that night. Katy ironically dressed up as a vampire while her boyfriend,John Mayer, suited up as a zombie. However, Kristen decided not to participate in the Halloween festivities. It would’ve been so cool if she came as Bella,lol!! Oh well, Stay tuned. Follow us on Facebook by Clicking Here. Follow us on Twitter by Clicking Here.