Eclipse is based on the novel by American author Stephenie Meyer. It's the third in a series of four modern-day teen vampire books, collectively known as The Twilight Saga. In order, the books are Twilight (2005), New Moon (2006), Eclipse (2007) and Breaking Dawn (2008).
The first two books have also been made into movies: Twilight (2008) and New Moon (2009). Breaking Dawn -- Part 1 is scheduled for release in November of next year.
The first two Twilight films grossed €909,725m from their worldwide cinema releases.
Teen Twilight fans are known as Twihards.
Official Twilight products include Just Bitten Lip Staining Balm, Immortal Body Liquid Shimmer and Mortal Glow Blushing Creme (twilightbeauty.com)
Christian Newswire reported in the US that the films were promoting the dangerous practice of sipping real blood among teens and adults.
The Irish Film Classification Office rated Eclipse 12A, due to "sequences of intense fantasy action, with unrealistic injury detail".
The soundtrack with features Muse, Florence And The Machine and Vampire Weekend, entered the Billboard chart at No2.
To avoid internet piracy, the film is opening simultaneously around the world this week.
Eclipse will be the first Twilight film to be released in the giant Imax format.