In the stories that Billy Black tells at the bonfire, the third wife was originally going to be played by Kristen Stewart. She did perform the scene but the director David Slade and author Stephenie Meyer thought it had an unintentional comical effect.
Kristen Stewart received her high school diploma by correspondence one week before filming Bella's graduation scene. She took a mock graduation photo with an extra so she'd have a photo of herself graduating high school.
The note Bella retrieves from her drawer that happens to be from Jacob is actually the same note that is used as the prologue of the 'Eclipse' novel. Just as in the novel, lines of text are scored out rather than erased.
Prior to the release of the movie, the Volvo company sponsored an online game in several countries, including the continental US, in which they gave away a car of the same make and color as Edward's silver Volvo featured in the Twilight Saga: The Twilight Saga: Eclipse (2010). This game was called, "Lost in Forks", and was a maze style game in which the player had to drive around the town of Forks, Washinton and be the fastest player to reach Bella's Graduation Party at the Cullen's house in the shortest number of road "forks". The game featured several locations featured in the books, such as: Bella's House, La Push Beach, The site of the New Born Battle, and the Lumber Mill. The player could also unlock several easter eggs, including wall paper, movie clips and plot secrets. Volvo announced the the shortest route possible to the Cullen's house was 11 forks.
Director David Slade originally spoke against the Twilight series, stating that he wouldn't go near the franchise. Shortly after he was announced as the director of Eclipse, he quickly withdrew his previous remarks, claiming it to be a joke he was doing to promote some comedy shorts.
The scenes of Victoria building her "army" were based on the novella 'The Short Second Life of Bree Tanner', written by Stephenie Meyer and distributed, in first draft form, to the cast. One particular line, given by Edward to Jane, indicates he knew about the alliance alluded to in the novella, but, with no proof, it was something he could do nothing about.
David Slade has stated that most of Nikki Reed's fight scenes at the climax were left out because the dailies that came back from the lab were underexposed and the shooting schedule would not allow him and the crew to reshoot her parts.
"The Cold One" is played by Peter Murphy, who was the lead singer of the English band Bauhaus. Their brief success during the late 1970s and early 1980s is considered by many music critics to have given birth to the "Goth" rock genre, and their debut single, "Bela Lugosi's Dead," introduced several elements into the "Goth" genre and subculture - including its interest in vampires (Bela Lugosi being the actor who played Count Dracula in Dracula (1931)). Therefore, Murphy's presence in The Twilight Saga: Eclipse (2010) is a tip of the hat to several layers of subculture that predate the "Twilight"-era vampire enthusiasms. Murphy's only other feature film appearance was in The Hunger (1983), also a vampire film, in which he sang "Bela Lugosi's Dead".
The original editor, Art Jones, was to be solely credited for the film. Three months before the film's release, however, Jones was abruptly released by the studio. In regards to that, David Slade later commented that although Jones' edit was good, Summit felt that it didn't have the intensity intended. Summit immediately brought back Nancy Richardson (who edited the first film) to recut and fine-tune the edit. However, Jones' name still made the final credits.
The trivia items below may give away important plot points.
Jasper introduces himself as Jasper Whitlock to a coven of vampires, but is often referred to as Jasper Hale in his modern life; this is because he adopted Rosalie's family name to pass himself as her twin brother.
In certain scenes, the Cullens irises are completely black rather than their usual golden topaz color. While never directly commented on in the movie, it is referred to in the novels as an indicator of a vampire's extreme hunger when the eyes go completely black.
When Bella visits Jacob after the newborn battle, a painting of the A-Ka-Lat "Top of the Rock" island formation off the coast of La Push Beach can clearly be seen behind Bella during her dialogue sides. According to actual Quileute tradition, prominent members of the Quileute tribe have been buried on the A-Ka-Lat island. The island is also known as James Island, which is not an allusion to the Twilight series character James.