Katy Perry & John Mayer -- Sooooooo Dating

Katy Perry and John Mayer don't need to say it ... they're definitely an item. The pair have been spotted all over town recently and last night ... our photog caught them coming out of a house party in Los Feliz. Not a lot of recording sessions…

Heidi Montag Hilarie Burton Hilary Duff Hilary Swank