So Shrek and sidekicks Donkey and Puss sail away to find Artie, the future King Arthur. Just as they leave, Fiona drops another bomb on her anti-social, kid-hating husband: There’s a little ogre on the way. Fiona stays behind at the palace, where Snow White, Sleeping Beauty, Cinderella and Rapunzel throw her a baby shower. The gifts include one of the seven dwarfs as a live-in baby sitter (“Don’t worry,” Snow White tells Fiona. “I have six more at home.”). Palace life is interrupted by an invasion of fairy-tale villains, led by Prince Charming, whose happy-ever-after was dashed by Shrek in the first two films. The prince takes over the realm, forcing Fiona to teach her posse of pampered princesses to stand up for themselves rather than wait for a man to rescue them. “A big part of this film is just the theme of taking responsibility, be it fatherhood or kingship or whatever,” said Nick Walker, head of layout on the animation team for “Shrek the Third.” WHO’S BACK: The whole gang returns, led by the key foursome of Shrek (Myers), Donkey (Murphy), Fiona (Diaz) and Puss in Boots (Banderas). Shrek’s still barking at everyone in his Scottish brogue, though married life brings out his softer side more and more. “What I love about the Scottish people, which is part of my heritage, is they go from, `I love you, come here,’ to `You get out of my house!”‘ Myers said. “Scottish people are hilarious when they’re angry. They shift gears so fast.” Also back: Fiona’s mom, Queen Lillian (Julie Andrews, who in a dizzy moment hums “My Favorite Things,” a tune she sang in “The Sound of Music”); King Harold (John Cleese); villainous Prince Charming (Rupert Everett); and ugly stepsister Doris (Larry King). WHO’S NEW: The main new face is Arthur Pendragon, or Artie (Timberlake), a bumbling teen who’s first seen getting his butt kicked by jock Lancelot in a jousting match at his high school. When Shrek, Donkey and Puss arrive with the news that Artie’s in line to become a king, it swells his head after a lifetime spent a rung lower on the social scale than the school dorks who play a medieval variation of Dungeons and Dragons. Timberlake, whose poster appears as a gag on Fiona’s bedroom wall in “Shrek 2,” recently split in real life from Diaz, but it was not their personal relationship that led to the “Shrek the Third” gig. The filmmakers rang him up after catching Timberlake on “Saturday Night Live.” “We had seen him on `SNL’ and were blown away by how funny he was,” said “Shrek the Third” producer Aron Warner. Shrek, Donkey and Puss also run across magician Merlin (Eric Idle), who used to be a teacher at Artie’s school until he had a nervous breakdown. Other newcomers include the quartet of princesses, haughty Snow White (Amy Poehler); long-haired Rapunzel (Maya Rudolph); obsessive clean freak Cinderella (Amy Sedaris); and narcoleptic Sleeping Beauty (Cheri Oteri). Regis Philbin joins the voice cast as Mabel, another ugly stepsister, while Captain Hook, seen briefly singing a Tom Waits song in “Shrek 2,” advances to a speaking role, with vocals by Ian McShane. There are hordes of others, from palace flunkies to medieval Valley Girls to a Wicked Witch singing Charlene’s sappy 1980s hit “I’ve Never Been to Me” as a torch song. It was a juggling act for the filmmakers, with so many new and returning characters competing for screen time. They stuck to one principle to balance it all. “Shrek is going to drive the story. That is our goal from day one,” said Chris Miller, who moves up from head of story on the last movie to make his directing debut on “Shrek the Third.” “When you have all these characters, a lot of them you want to spend a lot of time with. They’re interesting. They all have a place in this film. But at the end of the day, it’s supporting Shrek’s story.” WHAT’S BETTER: With three more years of refinements to computer animation, what isn’t better about “Shrek the Third”? The 350 people who worked on the film created more realistic fire and water images, developed ways to mimic how light behaves in the real world and even simulated the slightly seasick oscillations of live-action shipboard scenes, where the camera lags just a tick behind the rocking of the waves. They scrapped the basic computer models of Shrek and other lead characters they had worked with since the first movie and rebuilt them from inside out to take advantage of the subtler anatomy now possible. The filmmakers had to resist the urge to make external improvements so they could remain true to the look of the original film. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! “You feel you’ve got a lot to live up to, man,” Timberlake said about being the new kid on the block in the Shrek world. “Every character is so good. When you come into `Shrek,’ you definitely feel you have a lot to prove.” The gang is joined by a gargantuan cast as the filmmakers take advantage of advances in computer animation to load up on supporting players, among them magician Merlin, Captain Hook, wicked witches, ugly stepsisters and four of the fairy-tale world’s fairest princesses. Here’s a rundown of the players and their exploits for the film that hits theaters May 18: WHAT’S HAPPENING: Just when newlyweds Shrek and Fiona thought they could head home to peace and quiet in the swamp, Fiona’s dad, the frog King Harold, croaks. On his deathbed, he asks son-in-law Shrek to take over the throne of Far Far Away, a job the ogre dreads. Shrek’s only option: track down Fiona’s distant cousin Artie and groom him to become king. REDWOOD CITY Time to catch up with your ogre friend Shrek, his greenish bride, Fiona, and their two men Friday, the yammering Donkey and the overreaching Puss in Boots. The filmmakers behind “Shrek the Third” offered a sneak peek at their PDI-DreamWorks animation complex near San Francisco. From the 20 minutes of footage they showed, the film looks likely to meet expectations as one of summer’s hottest tickets. Key voice stars Mike Myers, Eddie Murphy, Cameron Diaz and Antonio Banderas return, with Justin Timberlake headlining the newcomers as geeky teenager Artie.