During the show the duo (who starred together in Still Alice) were seen hugging, laughing, clapping and getting all in to the haute casino game, reported People magazine.
Stewart, 25, and Moore, 54, entered wearing the latest pieces from the collection, a black fitted velvet suit on Stewart and a long-sleeve velvet emerald dress on Moore, which she accessorised with matching platforms and a diamond shooting star necklace.
More celebrities who stopped by were the adorable duo of Lily Collins and Lily-Rose Depp who wore matching LBDs, Depp's mother Vanessa Paradis, "Girls" star Jemima Kirke, Rita Ora, South Korean rapper G-Dragon and model Lara Stone.