The 49-year-old actor was tight-lipped about details for the project. "There are things that I cannot say that will shock the audience," he said. "I won’t tell you how [Gibson is] going to go about it... But I’ll tell you this much, the film he’s going to do is going to be the biggest film in history. It’s that good."
Caviezel, who also appears in the forthcoming film Paul, Apostle of Christ, added: "Braveheart, that’s a film that took a long time to be able to crack. The same thing for Passion. And the same thing for this. He’s finally got it. So that is coming."
The sequel, The Passion of the Christ: Resurrection, has been in the works for several years. Gibson first revealed the title of the film in 2016, explaining at the time that it will not be a straightforward "chronological telling" of Christ's resurrection.
Sections of the film will take place "in another realm", the director said, and will explore Christ's experiences in the three days between the crucifixion and the resurrection.
"You’re going all over the place," Gibson added. "What happened in three days?... I’m not sure, but it’s worth thinking about. Get your imagination going."
Oscar-nominated screenwriter Randall Wallace, who worked with Gibson on 1995's Braveheart, will write the script. "The evangelical community considers The Passion the biggest movie ever out of Hollywood, and they kept telling us that they think a sequel will be even bigger," Wallace told the Hollywood Reporter in 2016.
Although its scenes of graphic violence proved controversial, The Passion of the Christ was a box-office hit, making more than $600 million worldwide on a budget of $30 million.
It became the highest-grossing R-rated film ever released in the US (though it was later surpassed by 2016's Deadpool and last year's Logan). To this day, it is still the highest grossing non-English language film of all time; its dialogue was originally written in English, but translated into both Latin and a reconstructed form of Aramaic.