Ford is refusing to name the "well-known actor" who originally landed the part of Kenny in the acclaimed new movie, but admits Hoult wasn't even part of the cast in the weeks leading up to the first day of filming.
And the first-time director feels sure fate played a part in the end result.
He says, "The actor didn’t show up the first day he was due. He was attached for six months and we had made his costumes.
"It was so lucky and I cannot imagine anyone but Nicholas Hoult in that role. I had seen Nicholas’ tape a few weeks earlier and I was kind of kicking myself. I had a sick feeling inside that this guy was perfect for it and that I was working with another actor. But it just came together."
But replacing one of his leads at the last minute was the least of Ford's troubles - he also had to fund the film himself when finance fell through at the start of the world economic crisis.
Stumping up the $7 million (GBP4.3 million) he needed to make the movie, Ford had to shoot the film in just 21 days to avoid running over budget.
But Colin Firth, who stars in the film, credits the director for never losing his cool and always appearing to be in complete control, despite the huge financial pressure on him.
The Brit says, "He was always immaculately dressed, he was always calm. He made sure that any anxieties were not communicated to anyone else."
The Oscar-tipped movie also features Julianne Moore, Ginnifer Goodwin and Matthew Goode.