Speaking to Reuters in response to claims that the project cost $500 million to make, Gianopulos insisted that the figure, which surfaced in a New York Times article, is inaccurate.
"That's a ridiculous number," he said. "It has actually no relationship to the actual cost of the movie." However, he admitted that Avatar, James Cameron's first film since the record-breaking Titanic, was "quite expensive" to produce.
"There is no question about that. But viewed now, from the perspective of its completion and having seen it, it's a formidable work and money well spent," said Gianopulos, who heads up production on Fox's movie and TV output with Tom Rothman.
Asked if he believes that the sci-fi action film will turn a profit, he replied: "I have no doubt about that."
Avatar opens in cinemas worldwide on December 17.