Though Steven Spielberg's 3D Tintin film has yet to open in the U.S., the Hollywood filmmaker is already planning its sequel.

Spielberg — currently on the road promoting the U.S. release of The Adventures of Tintin: The Secret of the Unicorn on Dec. 21 — said he's already chosen the next tale about the intrepid, ginger-haired reporter he wants to bring to the screen.

For the next film, Spielberg and Peter Jackson intend to swap their Secret of the Unicorn roles: Spielberg will switch to producer, while Jackson will tackle the direction.

"It's being written right now and he's directing it after he does The Hobbit," Spielberg said of his New Zealand filmmaking colleague at an event on Sunday.

"We have the story and we have the book we're adapting from Hergé and we can't wait to get started."

The American filmmaker, a longtime fan who's wanted to make a Tintin film for nearly two decades, also revealed that the planned sequel will see the bumbling Thompson detective twins "have a much bigger role."

The Secret of the Unicorn, based on three of Belgian cartoonist Hergé's Tintin books (The Secret of the Unicorn, The Crab with the Golden Claws and Red Rackham's Treasure), opened first overseas in Europe, Asia and Russia earlier this fall. 

It arrives in North America having already achieved blockbuster status and approaching $250 million US at the global box office. The film had its North American debut in Quebec on Dec. 9.

Created by Hergé (the pen name of Georges Remi) in 1929, Tintin follows the kind-hearted young journalist, his beloved canine sidekick Snowy and tipsy friend Captain Haddock on globe-trotting adventures. The stories have enthralled generations of children: in 2004, fans worldwide celebrated the 75th anniversary of the series.

Along with the comic books, Tintin was also brought to life in a long-running magazine, on radio shows, in animated and live action films, TV programs, stage productions and even video games.