"It is a rare kind of beast, these movies," he told a news conference in Tokyo for the Japanese release of "Indiana Jones and the Kingdom of the Crystal Skull."
In the Indiana Jones series, the action-hero archaeologist, sporting his trademark khaki soft-hat, fights bad guys as he solves ancient mysteries.
Ford said that the Indiana Jones saga, which began 19 years ago, still excited him like "Christmas morning."
"I was going to get to play with a whole bunch of new toys. I was very excited about that opportunity," he said of the new film.
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Scriptwriter George Lucas said the entire cast was excited when Ford put the adventurer's costume back on for the latest film.
"It seems to happen on every movie, every Indiana Jones movie we do. There is this magic moment when Harrison appears on the set in his outfit and puts his hat on," Lucas said.
"That just transports everyone into a magic place. I don't know why. Even in 'Star Wars,' we don't have an iconic figure who does the same," he said.
The film has enjoyed immense success around the world, grossing $313 million in its opening weekend alone in the best debut this year.