Enlarge Dual roles: 300 star Gerard Butler plays the scientist father and an imaginary explorer.

No little girl is, either.

But bring together 300's warrior king Gerard Butler and Little Miss Sunshine herself, Abigail Breslin, and you have Nim's Island.

In the family film based on a children's book, the pair star as a scientist dad and his plucky daughter who live on a tropical Australian isle.

Butler's Jack researches plankton while keeping pesky pelicans at bay. "One time, I was sitting, talking to a pelican, and he goes behind me and flaps his wings," he says. "I looked like an angel on camera. I was sure he was going to nip me or rip my ear off."

Breslin's Nim hangs out with her animal buddies: sea lion Selkie, sea turtle Chica and a lizard named Fred.

"I was training all the time with the sea lions," says the actress, 11, who aspires to be a veterinarian. "They are smart but unpredictable, so you have to be prepared for everything."

Their idyllic life is upended when Jack's boat is lost in a storm, and Nim reaches out for help from e-mail pal and Indiana Jones-like explorer Alex Rover, who actually is the literary alter ego of a reclusive San Francisco author played by Jodie Foster.

Butler might play a marine biologist, but he saw plenty of action in his secondary role as the imaginary Rover, who comes to life for both Breslin and Foster. "When Nim reads a book about Alex Rover, suddenly I'm in an Arabian desert with evil captors, or I'm being tied up by African tribesmen," says Butler, who uses an American accent for Jack and his Scottish burr for Alex.

The production set up shop on Hichinbrook Island in North Queensland, Australia, which sits between the mainland and the Great Barrier Reef. "Actually, when I think about it, I already live on an island — Manhattan," Breslin says. "But I got to do stuff I would never, ever do, like climb up the side of a volcano."

Butler enjoyed his time with the young Oscar nominee. "Nim and her dad are best buddies. I don't think I could have done it as well with someone who didn't have Abigail's special talents. I learned a lot from her, how she would embrace an idea and go for it."

She also embraced the idea of a "swear pot," which nearly bankrupted Butler. "Me being from Scotland, I have a bit of a foul mouth. She fined me $2 each time. If I gave her extra, she would forget and not count it. It was hard to argue with her."

His losses did go to a good cause, "the Australian equivalent of the SPCA. But all I know is if she hadn't made it as an actress, she would have made a damn good lawyer."

Enlarge Photos by Walden Media Here we come: A zipline is part of the fun for Nim, played by Abigail Breslin, and Jodie Foster.