Mary-Kate Olsen joined her longtime friend Vladimir Restoin-Roitfeld last night in NYC to toast "RETNA: The Hallelujah World Tour" art show he curated with business partner Andy Valmorbida. Mary-Kate sported one of her signature furry pieces at the bash and was even seen sharing a high-five and laughing with her pals like Andy's brother PC. The fun event was part of a very busy Fashion Week for the designer. She and her sister Ashley kicked off the month with a party to celebrate their TEXTILE Elizabeth and James line and will debut their latest collection for The Row at a special presentation on Monday. Be sure to read all the latest dispatches from Fashion Week on Fab, Pop, Bella, and Fashionologie!