updated 09/05/2008 AT 11:45 AM ET
•originally published 09/05/2008 AT 12:20 PM ET
Mary-Kate Olsen raised the roof (by partying on it!) during a pre-Fashion Week bash in New York Thursday night.
The fashionista was among the first guests to arrive at Dazed & Confused magazine’s MINI rooftop bash, held in a converted loft space. A casual Olsen was there to check out psychedelic Brooklyn-based rockers MGMT, who performed at the party – but she arrived almost two-hours before the band took the stage. To pass the time, the starlet took a seat in the grass, sipped some beer and talked to her friends.
During the set, she danced along and not even some spraying beer halted her groove!
Also at the party: Gossip Girl actress Jessica Szohr, model Jessica Stam and Solange Knowles.
Reporting by Stephanie Prommer
Mary-Kate and Ashley are 21, rich, and inseparable as ever