VIDEO : Lady Gaga Charms the Pants Off Cast and Crew of 'American Horror Story'

PopSugar was on the ground at the Saturday night premiere of 'American Horror Story: Hotel' in Los Angeles, and got the whole cast talking about the show's newest and most exciting member: Lady Gaga ! While Gaga was heating things up with her fiance Taylor Kinney , PopSugar asked her costars what it's been like working with her on set. Matt Bomer couldn't help but gush, but he wasn't the only one with words of high praise. Co-creator Brad Falchuk called Lady Gaga "inspiring" and "fearless," while Kathy Bates described her as a "sweetheart."