During season six of "The Mary Tyler Moore Show", Moore appeared in a musical/variety special for CBS titled "Mary's Incredible Dream", which featured Ben Vereen. In 1978, she starred in a second CBS special, "How to Survive the '70s and Maybe Even Bump Into Happiness". This time, she received significant support from a strong lineup of guest stars: Bill Bixby, John Ritter, Harvey Korman and Dick Van Dyke. In the 1978–79 season, Moore attempted to try the musical-variety genre by starring in two unsuccessful CBS variety series in a row: "Mary", which featured David Letterman, Michael Keaton, Swoosie Kurtz and Dick Shawn in the supporting cast. CBS canceled the series. In March 1979, the network brought Moore back in a new, retooled show, "The Mary Tyler Moore Hour", which was described as a "sit-var" (part situation comedy/part variety series) with Moore portraying a TV star putting on a variety show. The program lasted just 11 episodes.