Tilly is Eddie Menuek's ex-girlfriend, portrayed by Mary Gallagher.
Tilly left Eddie when she could not cope with his irrational, crazy behavior. In "The One Where Dr. Ramoray Dies", she comes to the apartment to bring back a fish tank to Eddie (without a goldfish which Eddie then believes Chandler Bing killed). After she leaves, Eddie immediately accuses Chandler of sleeping with her.