What if identical twin girls suddenly met the sister they never knew they had? That's the premise of 'Sister Sister', a 1994 entry in ABC's TGIF block. The two families move in together as the engaging duo of Tia and Tamera Mowry charm viewers by breaking the fourth wall and addressing them directly. ABC moved the show to another night for season two, ratings dropped and out came the cancellation axe. But the WB picked up the show and it ran four more years. The theme song was written by Tim Heintz, Randy Petersen, and Kevin Quinn. Starting in season five the twins themselves performed the theme, now revised by Kurt Farquhar to reflect the girls' growing maturity. 0:00 Opening titles, season one. 0:56 Opening titles, season four. These new visuals first appeared in season three. 1:39 Opening titles, season six. Revised version of the theme. 2:20 End credits, series finale. Most episodes had no end credits music. But some did feature a placid instrumental based on the show's theme. 2:54 Paramount.