<P> When Good Morning, Miss Bliss was retooled as Saved by the Bell, four actors and their respective characters from the original series were brought over to the new series: Gosselaar, Diamond, Voorhies, and Haskins . The rest of the cast was fired, and Engel sought to replace them with new characters who would complement the old ones . </P> <P> The first of the new characters, A.C. Slater, was conceived as a young John Travolta type who would be an army brat and wear a leather jacket . He was originally conceived of as Italian - American . However, when all efforts to cast the character were unsuccessful, Engel asked that the part be opened up to other races . Two days later, Mario Lopez, a dancer and drummer of Latino descent from Kids Incorporated auditioned for the role . Lopez was, by far, the best actor who auditioned, and was cast . </P> <P> For Kelly Kapowski, the love interest of both Zack and Slater, producers were able to narrow the field down to three actresses: Tiffani - Amber Thiessen, Elizabeth Berkley, and Jennie Garth . Engel had originally met Thiessen in 1988 while casting for Good Morning, Miss Bliss and was impressed with how much her acting had improved . He wanted her for the role, believing she had the perfect all - American girl appeal for the role, while others felt that Berkley, as the more experienced actress, would be a more reliable choice . Ultimately, Engel convinced the others after a read - through with Lopez, and Thiessen received the role . </P> <P> Engel and the other producers did not want to lose Berkley, however, as she was the strongest actress they'd seen during casting . Berkley originally auditioned for the role of Karen, a love - interest of Zack's on Good Morning, Miss Bliss, but lost the role because she was so much taller than Gosselaar at the time . Engel believed that, now that her height was more even with the rest of the cast, she could be perfect . They were not having much luck in casting the third new character, Jessie Spano, who was conceived as a strong, feminist activist and a straight - A student, so Engel suggested offering the role to Berkley, who gladly accepted it . </P>

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