Jon Hamm and January Jones attend the much awaited premiere of Mad Men's 5th season at the Arclight; New York comes to L.A. as Kate Spade throws a party for Brad Goreski's new book; Charlize Theron and Katie Holmes celebrate their awesome stylists at Soho House and more! It was another action-packed Wednesday here and we have all the details on the events that went down in Los Angeles and the notables who attended in this installment of Last Night's Parties!

-[Jon Hamm, Jennifer Westfeldt Via]