Nikki Reed was the one who got the producers to add Robert Pattinson's songs to the film. Reed secretly started recording him from her laptop, while he was singing, and playing his guitar. She then took it to the film producers, were they fell in love with his songs. The next day, they asked Rob if he could sing a few of his songs for the soundtrack, and he accepted.
In the scene where Bella goes to the Cullens house for the first time, when Nikki Reed's character had to break the bowl, she actually cut her hands. This is why she is wearing gloves for the scene in the film.
Stephenie Meyer wrote a parallel novel (unfinished) to "Twilight" called "Midnight Sun". It tells the story of the first book from Edward's point of view. In it, he comments that the arrival of Bella to the school has all of the boys "acting like they're in first grade and she's the shiny new toy". This thought is spoken aloud by Jessica during Bella's first lunch in the cafeteria.
As soon as Robert Pattinson was cast, he moved to Oregon and began working on his character, both physically and mentally. He worked out five hours a day with a trainer: learning to fight, play baseball, and do stunts. He also had to learn to drive and get an Oregon driver's license.
When Edward and Bella are standing in the doorway of the Cullens' kitchen, there is a chess set on the dining room table behind them with red and white pieces, like the cover of 'Breaking Dawn', the final novel in Stephenie Meyer's 'Twilight' saga.
Peter Facinelli was the second choice to play Carlisle Cullen. When he found out that he lost out on the final round of auditions, he wrote a note to Catherine Hardwicke, saying, "I hope to work with you sometime." At the last minute before shooting, the original actor withdrew due to shooting conflicts. Hardwicke then offered the role to Facinelli, who immediately took up. He had to dye his hair blond before starting work.
At the cafeteria salad bar, Bella drops an apple which Edward picks back up and then cradles in his hands, copying the cover image of the Twilight novel. On the one of the DVD's special features Catherine Hardwicke said that took them 13 takes to get it right.
Kristen Stewart suggested the prom dance song "Flightless Bird, American Mouth" by Iron & Wine for the film and the director decided to use it. The song made it onto the official soundtrack and is the song most associated with the Twilight films. Iron & Wine recorded a "wedding version" of the song for Edward and Bella's wedding in a later movie.
For the role of Edward Cullen, Robert Pattinson flew from England to director Catherine Hardwicke's house to audition. There, he and Kristen Stewart, who was already cast as Bella Swan, rehearsed the "Love Scene"/"Meadow Scene" on Hardwicke's own bed.
The apple on the cover of the book is not only a symbol for the forbidden; in Scandinavian mythology the apple is a symbol for eternal youth and beauty. However, on her official website Stephenie Meyer states that she used the apple on the book cover because of the past literary connections (causing trouble every time) like in Snow White and the Golden Apple Paris gives to Aphrodite in Greek Mythology and because to her apple represents "choice".
All of the Cullens can be seen wearing jewelry with the same symbol on it. Edward, Jasper, and Emmett all had the same wristband, and Alice and Rosalie had similar necklaces with the symbol on it; Esme had a bracelet and Carlisle had a ring.
Kellan Lutz intended on keeping his natural curly hair for the role of Emmett Cullen. However, his previous role in Generation Kill (2008) required a buzz cut and his hair didn't grow fast enough for the filming of Twilight (2008).
The Cullen family crest (seen worn by all the Cullens) is a lion with a hand over its head, and a downward pointing chevron with 3 clovers. The lion was added because of the famous line "And so the Lion fell in love with the Lamb", but the other portions (chevron, clovers, and hand) are from the actual Cullen Coat of Arms, although there are fewer clovers (2), more hands (3), and a sheaf of wheat on the real one.
Henry Cavill was Stephenie Meyer's first choice to play Edward. However, but by the time production was to begin, he was 25 years old, and no longer looked the part of a 17-year old. He was then offered the part of Carlisle Cullen but turned it down due to his commitment with The Tudors (2007).
The original release date for Twilight (2008) was December 12, 2008. When the release date for Harry Potter and the Half-Blood Prince (2009) was moved from November 21, 2008, to July 17, 2009, Twilight's release date was moved forward to November 21 in an attempt to fill the Harry Potter gap.
The song playing on the background when Bella comes to "have dinner" at the Cullen's is the aria "Libiamo" from La Traviata. "Libiamo" literally means "Let's Drink", which is exactly what the Cullens do when they "have dinner".
Prior to the release of the soundtrack featuring Carter Burwell's scored theme of "Bella's Lullaby", Yiruma's piano composition, "River Flows in You", was largely and erroneously believed by many fans to be featured in the movie as the lullaby. This was due to a popular fan site including the piece by Yiruma on a playlist of songs that served as their personal soundtrack for the Twilight book. While this song was how the fan site imagined the lullaby to sound (and subsequently thousands of fans online), it was never a part of the movie.
MTV Films & Maverick Films were the original owners of the rights to produce the film. Paramount was set as the distributor. Eventually MTV Films wasn't able to get a script they felt was good enough for the film and Summit Entertainment ended up getting the rights and actually producing and distributing the film.
Catherine Hardwicke has said that she filmed a scene with Robert Pattinson taken directly out of "Midnight Sun", the unfinished novel by Stephenie Meyer telling the story of Twilight through Edward's perspective. According to her, this scene will be on the DVD.
The beer that Charlie drinks in the movie is "Rainier Beer", a brewing company originally based out of Seattle, Washington. Charlie refers to it as "vitamin R", which is a common nickname for Rainier Beer.
Gil Birmingham had a role in the Season 2 episode "Buffy the Vampire Slayer: Inca Mummy Girl (#2.4)" (1997) of Buffy the Vampire Slayer (1997). This season primarily deals about the romance between Buffy (a teenage girl) and Angel (a vampire).
While doing location scouting work in La Push, Catherine Hardwicke and the crew saw people surfing and suggested to screenwriter Melissa Rosenberg to add beach surfing scene. Rosenberg agreed and added it but the scene had to be scrapped because of budget constraints.
The author of the original books can be seen next to a laptop ordering a vegetarian sandwich in the diner at the beginning of the scene where Charlie asks Bella if she likes the boys in town.
Robert Pattinson unknowingly contributed two songs to this film. Apparently, he didn't know that "a mysterious third party" had given the director a copy of music he had recorded years ago. She decided to use two of the songs, and he was surprised to hear them when viewing early film footage. The songs are: "Never Think" [playing during the restaurant scene] and "Let Me Sign" (plays during the scene where Edward has to drink Bella's blood to save her). Pattinson said he was overwhelmed by how well "Let Me Sign" fit into the film.
When the high school students are getting ready for prom, Eric tells Bella he'll need to borrow her iPod for dance music. Kristen Stewart (Bella) actually suggested the song "Flightless Bird, American Mouth" by Iron & Wine to play during the dance scene Bella shares with Edward at prom.
In the script, the climatic Bella's "limbo" scene was intended to be an underwater sequence but budget constraints will not allow the scene to be filmed. As the alternative, outtakes from other scenes of Bella and Edward together were used, albeit digitally modified.