* ActorAllusion:
** Dianna Agron [[{{Series/Glee}} once again]] used to date the quarterback and is now one of the misfits.
** Henri tells Number Four "you have no idea what you are capable of". This is a nod to Timothy Olyphant saying a similar line ''Die Hard 4.0''.
* ActorInspiredElement: Number Six is Australian because Teresa Palmer wanted to speak in her natural voice.
* CastTheExpert: Alex Pettyfer was already trained in stunt work and combat from ''{{Film/Stormbreaker}}'', making him an apt fit for Number Four.
* DawsonCasting: Played straight as 24-year-old Dianna Agron, 22-year-old Jake Abel and 20-year-old Alex Pettyfer play high school students. 24-year-old Teresa Palmer as 16-year-old Six, too. However, it's averted with Callan [=McAuliffe=] who was 15 at the time of filming, and Greg Townley who was 14: their characters' ages.
* DeletedRole: Karen Allen filmed some scenes as Sam's mother, but they were cut from the film.
* DyeingForYourArt:
** Alex Pettyfer dyed his blond hair brown for the beginning of the film. Jake Abel dyed his blonde hair brown for the duration of the film. Callan [=McAuliffe=] had his hair dyed darker for the film, but claims to have lost track of its original color because he's dyed it other colors for roles before.
** Teresa Palmer went through three months of sword training, wire work and weight training to prepare.
* FakeAmerican: Alex Pettyfer is British.
* FollowTheLeader: The author Pittacus Lore outright wrote the books to follow in the footsteps of ''Literature/HarryPotter'' and ''{{Literature/Twilight}}'' to create a new film franchise.
* NamesTheSame:
** So Mogadorians travelled to Paradise, Ohio? Should only take about an hour... If you mean Mogadore, OH, a town just outside of Akron.
** [[LordOfTheRings Lorien is also kinda near Mordor]].
* StillbornFranchise: Not the novels, but the film series that was intended to be released alongside the novels was shelved indefinitely due to lukewarm reception and mediocre box office profits.
* RomanceOnTheSet: Alex Pettyfer and Creator/DiannaAgron became [[PortmanteauCoupleName Dialex]] for a bit.
* WhatCouldHaveBeen: Creator/SharltoCopley was cast as Henri, but dropped out due to scheduling conflicts, and was replaced with Creator/TimothyOlyphant.
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