Zac Efron shows up on time for Hublot's celebration of new brand ambassador Kobe Bryant; Jon Hamm, Christina Hendricks, Elisabeth Moss and the rest of the "Mad Men" cast turn out for the Season 6 premiere; Jason Bateman and Emma Rossum make memorable appearances at a gala benefiting the Alzheimer's Association; Neil Patrick Harris attends Hollygrove's Norma Jean Gala; Christina Ricci and Rosie Huntington-Whiteley look stunning at the BlackBerry Z10 launch; Leandra Medine, Liberty Ross and Brooke Davenport shop the Christian Dior pop-up at Maxfield—it was a very busy Hump Day here in L.A. and we have the rundown on it all in today's edition of Last Night's Parties.

Rachel Bilson January Jones Emmy Rossum Zac Efron Jason Bateman Jay Manuel Ron Howard Neil Patrick Harris Garcelle Beauvais-Nilon Mad Men Debby Ryan John Slattery Vincent Kartheiser Rich Sommer Christina Ricci Julia Ormond Brian Grazer Josh Duhamel Jason Alexander Jon Hamm Elisabeth Moss Perrey Reeves Christina Hendricks Brad Goreski Alison Brie Jennifer Westfeldt Lauren Miller Kaley Cuoco Johnny Galecki Sharon Lawrence Tim Allen Craig Robinson Kobe Bryant Mark Salling Robert Buckley Zelda Williams Jimmy Kimmel Ashley Jones Kiernan Shipka Taran Killam Cecconi's Jesse Williams Matthew Weiner Zachary Levi Sunset Tower Rob Morrow Leandra Medine Maxfield Jessica Pare Rosie Huntington-Whiteley Busy Philipps Beth Behrs Cobie Smulders Merle Ginsberg Constance Zimmer David Burtka Mayim Bialik Brooke Davenport Willow Bay Ben Feldman Aaron Staton Sofia Milos Alexandra Chando Irena Medavoy The Beverly Hilton hotel Barrett Foa Kunal Nayyar Chloë Grace Moretz Annabelle Wallis Vanessa bryant Pia Toscano Diane Ladd Melissa Rauch Clea DuVall Claudia Lee Robert Morse Liberty Ross Jay R. Ferguson Jack Wagner Tegan and Sara Sarah Rafferty Alex Lombard DGA Theater Mad Men season 6 TCL Chinese Theater Hublot Celebrates New Brand Ambassador Kobe Bryant AMC's "Mad Men" Season 6 Premiere Teyonah Parris 21st Annual "A Night At Sardi's" Gala Benefiting The Alzheimer's Association Shanola Hampto Hollygrove's 1st Annual Norma Jean Gala BlackBerry Z10 Launch Sara Quin Tegan Quin Nathalie Emmanuel Alex Plank Dior & Maxfield Celebrate The Launch of Raf Simons' Debut Pret-A-Porter Collection For Spring With A Cocktail & In-Store Pop-Up Mad Men Season 6 premiere after party