Penny Marshall
Garry Marshall, creator and then part-time writer for "Happy Days", cast Marshall and Cindy Williams to guest on an episode of the show. The installment, titled "A Date with Fonzie", aired on November 11, 1975 and introduced the characters Laverne DeFazio and Shirley Feeney (played by Marshall and Williams, respectively). In that episode, Laverne and Shirley were a pair of wisecracking brewery workers who were dates for Fonzie (Henry Winkler) and Richie (Ron Howard). The pair were such a hit with the studio audience that Garry Marshall decided to co-create and star them in a successful spinoff, "Laverne & Shirley" (1976–1983). The characters of Laverne and Shirley appeared in five more episodes of "Happy Days". In 1982 at the beginning of "Laverne & Shirley"s eighth season, Williams left the show due to her pregnancy. Marshall continued with the show, but it was canceled after the season's final episode aired in May 1983.
Happy Days (TV theme)
The song was first recorded in 1974 by Jim Haas with a group of other session singers for the first two seasons. These versions of the song were used only during the closing credits of Seasons 1 and 2, with an updated version of "Rock Around the Clock" by Bill Haley and His Comets used as the opening theme. The song was re-recorded in 1975 with different lyrics for both the opening and closing credits for Seasons 3 through 10. Pratt & McClain released the song as a single in 1976 from their album "Pratt & McClain Featuring Happy Days". Bobby Arvon recorded an updated version of the song in 1983 for the opening and closing credits of Season 11, with the same lyrics as the version used for seasons 3-10.