Before ABC axed ‘Roseanne,’ many of the child actors were already becoming fan favorites. Jayden Rey, 9, and Ames McNamara, 12, are the young break out stars from the series reboot. Rey played Mary Conner, Roseanne's adorable African-American granddaughter. McNamara was Mark, Roseanne’s gender fluid grandson. Their starring roles made them overnight sensations. Before they landed the landmark roles, they were trying to make it in showbiz.