Party Photos of the Week! Lena Dunham, Jessica Chastain, and More

The parties this weekend spanned coast to coast! It was a cross-country affair for the 65th Annual Writers Guild Awards, where stars gathered in Los Angeles and New York to honor the best writers in the business. On the east coast, Girls creator Lena Dunham celebrated her win for Best New TV Series at the B.B. King Blues Club & Grill with Gina Gershon, and in Los Angeles, Jessica Chastain and her Zero Dark Thirty director Kathryn Bigelow came out to support the film’s screenplay writer, Mark Boal, who took home the award for Best Original Screenplay. Click through the gallery to see all the stars who attended this week's biggest parties.