Who? Singer Katy Perry
What? A sheer and silky print dress, stocking-effect tights and her purple-black locks. Also present was love interest Robert Ackroyd and fellow Summertime Ball performer Jessie J
Where? Cirque Du Soir nightclub in London, 10 June
Bonus info: Point 1: Katy seems to be a fan of Jessie's as she took to Twitter to inform the singer: "ur hot".
@JessieJ ur hot.-- Katy Perry (@katyperry) June 10, 2012
Point 2: Katy Perry makes it look really difficult to leave a club incognito!