Christy Carlson Romano is sharing a rare throwback photo of her high school classmates Scarlett Johansson and Jack Antonoff. The former Disney Channel actress, 42, posted a series of photos from the past to Instagram on Tuesday, March 24, as she announced her new memoir, Once Upon a Trainwreck: The Fall and Rise of a Child Star, which is due for publication in October. Among the throwback snaps is a 2002 yearbook photo from her time at the Professional Children's School in New York City, which Johansson and Antonoff also attended.