* ActorSharedBackground: They worked in Heath Ledger's Australian background to be an actual part of the character, including having Kat ask him if the accent was real or faked.
* DawsonCasting: One of the most notable aversions, all of the main cast was between 18 and 20 during the filming of the movie playing high schoolers (Krumholtz was the oldest, and he was barely 21 when the movie premiered). Some of the supporting cast were a little older, though - Gabrielle Union (Chastity) and Susan May Pratt (Mandella) were 27 and 25, respectively.
* HeyItsThatGuy: [[Series/TheWestWing CJ Cregg]] is Ms. Perky! [[TheSecretWorldOfAlexMack Alex Mack]] is Bianca! [[Disney/TreasurePlanet Jim Hawkins]] is Cameron! [[{{Series/Numb3rs}} Charlie Eppes]] is Michael! And, of course, [[Creator/HeathLedger the]] [[Film/TheDarkKnight Joker]] is Patrick!
** Hey, it's Tommy and Alissa from ''[[Series/ThirdRockFromTheSun 3rd Rock]]''! And they're ''still'' dating even though their names are different!
*** [[Film/GIJoeTheRiseOfCobra COOOOOBRAAAAA!!!!!]]
*** Wait a second, that's ''[[Film/{{Inception}} Arthur]]''?
** Bianca's BFF is head of [[Film/BringItOn the Clovers cheer squad]].
** From the series: [[CampRock Tess]] and [[Series/NedsDeclassifiedSchoolSurvivalGuide Moze]] are sisters and [[{{Series/Heroes}} Monica Dawson]] is the head cheerleader.
* OldShame: Averted, a lot of people expected HeathLedger to continue in the teen comedy genre but he instead refused a lot of similar roles until he started to get the parts he wanted like in ''ThePatriot'' and ''AKnightsTale''. Despite this, he ''didn't'' consider this film to be an old shame, just not where he wanted to take his career.
* OohMeAccentsSlipping: Ledger's accent is sort of half-Amercian, half-Australian. Possibly justified in-universe as he's revealed to be from Australia originally, but to have lived in America for more than a year prior to the film starting.
* RomanceOnTheSet: Joseph Gordon-Levitt dated both Larissa Oleynik ''and'' Julia Stiles after filming... not at the same time. The main cast apparently became fairly close friends, regardless.
* ThrowItIn: Stiles's tears during the poetry reading scene were apparently unscripted, as was the brief shot of Ledger playing with the Bunsen burner near the opening of the film.
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