Laurette Spang appeared on the series 6 times as 3 different characters.
When Fonzie and his date enter the prom, she tells Fonzie she's going to speak to her friend Doris. Fonzie then says "I'll tell you when you can go", pauses, then says "You can go." This is the exact same dialogue Sylvester Stallone's character Stanley tells his girlfriend Frannie in "The Lords of Flatbush", which co-starred Henry Winkler, who based his performance of Fonzie on Sylvester Stallone's portrayal of Stanley.