X2 (often promoted as X2: X-Men United and internationally as X-Men 2) is a 2003 American superhero film based on the X-Men superhero team appearing in Marvel Comics. It is the sequel to 2000's X-Men, and the second installment in the X-Men film series. The film was directed by Bryan Singer, written by Michael Dougherty, Dan Harris, and David Hayter, and features an ensemble cast including Hugh Jackman, Patrick Stewart, Ian McKellen, Halle Berry, Famke Janssen, James Marsden, Rebecca Romijn-Stamos, Brian Cox, Alan Cumming, Bruce Davison, Shawn Ashmore, Aaron Stanford, Kelly Hu, and Anna Paquin. The plot, inspired by the graphic novel God Loves, Man Kills, pits the X-Men and their enemies, the Brotherhood, against the genocidal Colonel William Stryker (Brian Cox). He leads an assault on Professor Xavier's school to build his own version of Xavier's mutant-tracking computer Cerebro, in order to destroy every mutant on Earth and to save the human race from them.
Development began shortly after X-Men (2000). David Hayter and Zak Penn wrote separate scripts, combining what they felt to be the best elements of both scripts into one screenplay. Michael Dougherty and Dan Harris were eventually hired to rewrite the work, and changed the characterizations of Beast, Angel, and Lady Deathstrike. Sentinels and the Danger Room were set to appear before being deleted because of budget concerns. The film's premise was influenced by the Marvel Comics storylines Return to Weapon X and God Loves, Man Kills. Filming began in June 2002 and ended that November. Most of the filming took place at Vancouver Film Studios, the largest North American production facility outside of Los Angeles. Production designer Guy Hendrix Dyas adapted similar designs by John Myhre from the previous film.
X2 was released in the United States on May 2, 2003. It received positive reviews from critics, who mostly praised the storyline, action sequences and acting of the film. With its critical success, it grossed over approximately $407 million, and received eight Saturn Awards nominations.