Johnny Galecki is a Belgian-born American actor, best known for his roles as David Healy in Roseanne, Rusty Griswold in National Lampoon's Christmas Vacation, and as Leonard Hofstadter in The Big Bang Theory.
The film chronicles Henson's life, from the early years of his career to the creation of properties like the Muppets, Sesame Street, and The Dark Crystal, and also focuses on his creative and romantic partnership with his wife Jane Henson.
