Free Online HD on Lookmovie. The hour-long special hosted by Carol Burnett features musical and comedy routines with Carol and guest performers, Carl Reiner, Whoopi Goldberg, and Robin Williams. The four comedians, Burnett, Reiner, Goldberg and Williams introduce the show from lecterns in a mock-academic recitative number, called "Laughter," in which they examine laughter's "primary root and cause."