French director Louis Leterrier was a regular fan of "The Fast and the Furious" when the multi-billion-dollar franchise started more than two decades ago. Now he is finishing it.

"I was a fan, buying my ticket on the Champs Elysee in 2001, who became a director and now I'm ending the franchise," Leterrier told AFP. "That never happens!"

The 49-year-old has taken over directing duties for the final two instalments -- including "Fast X" which hits theatres around the world next week. 

His goal, he told AFP, was to reconnect with "the integrity" of that first instalment way back in 2001.

"Well, there's still some pretty crazy things in there but we are at least on Earth," Leterrier said, referring to the last instalment, "Fast 9", which upped the ante by driving a car into outer space. 

The sprawling series has followed the adventures of Dom Toretto (Vin Diesel), an ex-criminal who becomes a street racing star in Los Angeles, and the gang which he considers his family. 

From a relatively modest thriller focusing on pimped-out cars, the franchise has grown to challenge the superhero behemoths of Hollywood, raking in more than $6.6 billion at the global box office. 

As the budgets have ballooned, so have the outlandish stunts and storylines. But Letterier said he wanted to bring things back down to Earth. 

Nothing is impossible anymore when it comes to stunts, he said, "but I don't want to lose the viewer in the impossible. 

"I want to push reality, to push cinema into another dimension, but above all I have to tell human stories."

This time around, Dom and his friends battle the son of an enemy they defeated back in the fifth instalment, played by Jason Momoa ("Aquaman"). 

They are joined by regulars such as Michelle Rodriguez and Jason Statham, as well as Oscar winners Charlize Theron and Brie Larson.

As with the other films in the series, viewers are taken to the four corners of the world, from Rio de Janeiro to London, and Antarctica to Portugal. 

"I'm going back to the essentials. And that means getting out of the computer and back into the physical world," Leterrier said. 

"The cars are really being driven. The fires are actually real."

The final chapter is due next year and Leterrier knows where it is going. 

"The sequel was not shot at the same time but it was conceived at the same time, so we know where the film will end," he said.

"It will be a human climax. The end will not be just a big explosion." 

His lips are sealed on the details, but he promised that it would go to "a place where Hollywood does not usually go... and back to where it all began".

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