Iain Armitage was only nine years old when we first met him on "Young Sheldon," but now he's nearly an adult, and he looks a whole lot different.

Neil Patrick Harris breaks down a few of his most iconic characters, including 'Harold & Kumar,' 'Doogie Howser, M.D.,' 'How I Met Your Mother,' 'Hedwig and the Angry Inch,' 'Starship Troopers,' 'Gone ...

In an Instagram update, the 17-year-old actor posted photos from a get-together with Wallace Shawn, who played Dr. John ...