From Primetime to Daytime: The series premiere of The Facts of Life (1979)

 The Facts of Life, spun off from Diff'rent Strokes, got a head start on the rest of the NBC lineup by launching in August 1979, although after the first four weeks, the series was placed on hiatus until the following spring, during which time, the producers began to overhaul the cast.

In the opener, "Rough Housing", Blair (Lisa Whelchel) thinks she has it in the bag as the Harvest Queen, but is jealous when Cindy (Julie Ann Haddock) is nominated instead. The Strokes cast (Conrad Bain, Todd Bridges, Gary Coleman, & Dana Plato) guest star.

At least here, the theme is a duet between co-author Gloria Loring (Days of Our Lives) and co-star Charlotte Rae, though that would change.