 "Dragons' Den" became one of the most-watched shows in CBC history, with around two million viewers per episode.Coxe attributed the show's success in large part to O'Leary's presence.In 2009, the American version of "Dragons' Den", "Shark Tank", began, and "Shark Tank" executive producer Mark Burnett invited two of the CBC "Dragons' Den" investors, O'Leary and Robert Herjavec, to appear on the show.