Joan Jett, Alison Mosshart, and other rockers ring in the 2013 Sunset Strip Music Festival at House of Blues; Kelly Osbourne, Lauren Conrad, Lance Bass, and many more step out for this year's Young Hollywood Awards; Kendra Wilkinson and Jessica Hall show their support at a charity event hosted by Playboy Radio; Minnie Driver and Christopher Wolfe attend the I Give It A Year screening; Demi Lovato, Diane Kruger, Zooey Deschanel and other network stars go to the FOX All-Star party; Simon Cowell, Kelly Rowland, Andy Samberg, Minka Kelly and more field questions at Day 9 of the Summer TCA Tour—let us give you a peek inside all of Thursday's top events in L.A. with this edition of Last Night's Parties.

Seth Green Mario Lopez Diane Kruger Andy Samberg Zooey Deschanel Amy Poehler Nicole Beharie Cat Deeley chris lowell Kelly Rowland emily deschanel Magnolia Pictures Lance Bass Casino Night Beverly Hills Brenda Song Kelly Osbourne kristen renton Kristen Schaal Gordon Ramsay Zachary Quinto minnie driver West Hollywood Sunset Strip Joan Jett Lili Taylor David Boreanaz Giovanni Ribisi Alyssa Milano Kendra Wilkinson Simon Cowell Minka Kelly Ian Somerhalder Christopher Mintz-Plasse Dominic Monaghan Kat Von D Marisa Lauren W Hollywood Demi Lovato Young Hollywood Awards House of Blues Alison Mosshart Carmen Electra Fox Vanessa Minnillo Rodney Bingenheimer Crystal Hoang Andre Braugher Dave Franco Mackenzie Crook David Faustino Crystal Reed Sophie Simmons Jake Johnson Hannah Simone Max Greenfield The Broad Stage Holland Roden Jessica Hall Annabeth Gish Keith David Margaret Cho Jackson Rathbone Laura Marano Bobby Alt ArcLight Hollywood Television Critics Association Christa B. Allen Orlando Jones Geoff Stults Bob Guiney Scott Grimes Bailee Madison Katie Cazorla Beth Grant Cody Simpson Judi Shekoni Len Wiseman Lamorne Morris Mika Newton Mary Carey Joe Lo Truglio Terry Crews Danny Excess Paulina Rubio Liam James Tara Lipinski Alana Curry Ray Luzier Garret Dillahunt Erin Kristine Ludwig Britt Ekland Lloyd Klein Danielle Vasinova Jillian Rose Reed Kit Harington Michael Ealy Aaron Sanchez Allison Holker