Paul Greengrass didn't plan on making another 'Bourne' movie.
Greengrass has admitted that the thought never crossed his mind to make a follow-up to 2004's 'The Bourne Supremacy' and 2007's 'The Bourne Ultimatum' because he'd completely forgotten about the action spy thriller franchise.
He said: "I didn't spend the last seven or eight years thinking I would making another 'Bourne' film. I was always proud to have done them, but it had slipped into the rear-view mirror and I was very comfortable with that."
Lead star Matt Damon - who plays the titular role of James Bourne - had also thought there would never be any more movies until he started meeting with Greengrass and those meetings started to excite the pair.
He told Empire magazine: "Every time Paul and I talked, 'Bourne' would come up. It was 30 conversations over the course of the years. Sometimes we'd only talk about it briefly, but those conversations became longer more frequent."
However, the 60-year-old filmmaker almost lost his lead role in 2003 when Damon announced he was planning to quit before he'd started filming but he was eventually persuaded otherwise.
Greengrass said: "I was tearing my hair out. He and I didn't know each other. Matt had seen a couple of films I'd made, but there was nothing to suggest I would necessarily come through with a big commercial action movie. But in the end we said, 'F*ck it, we'll do it."
The movie went on to make $288 million worldwide and lead to the pair, who barely knew each other, becoming best friends.
Of their friendship now, Greengrass said: "I love him like a brother."