Shop Celebrity Style: Watch out 'Gossip Girl' fans there is a new girl on the scene who may be stealing Nate Archibald's heart. Columbia Student, Juliet, aka Katie Cassidy, has been spotted all over the streets of NYC with hottie Nate Archibald and sporting one seriously chic Yigal Azroual nude sheath. She added a pop of color with her Dolce & Gabbana blue leopard print pumps and a gray Carlos Falchi oversized tote. She opted for delicate jewelry, including a Tiffany & co. key pendant necklace and Diana Warner cuff. Serena Van Der Woodsen better watch out!