James Cameron has revealed that two of his Avatar sequels may not happen – if the next instalments "don't make enough money".
The Titanic director has announce plans to make four sequels to the smash hit first Avatar movie, which was released nearly a decade ago.
Filming of the sequels is expected to take place in the United States and New Zealand.
Kiwi actor Duane Evans Jr, who played Vinnie's son Michael in Shortland Street, is confirmed as a member of the oceanic clan Metkayina in the Avatar sequels. The 14-year-old actor joins a cast of young stars as the children of characters from the original Avatar.
In an interview with Vanity Fair, Cameron conceded that if Avatar 2 and 3 don't perform well at the box office, plans to release the fourth and fifth instalments could easily change.
"Let's face it, if Avatar 2 and 3 don't make enough money, there's not going to be a 4 and 5," he said.
"They're fully encapsulated stories in and of themselves. It builds across the five films to a greater kind of meta narrative, but they're fully formed films in their own right, unlike, say, The Lord of the Rings trilogy, where you really just had to sort of go, 'Oh, s**t, all right, well I guess I better come back next year.'
"Even though that all worked and everybody did."
Cameron has defended a delayed start to the Avatar project, blaming complex underwater motion-capture technology - something which he says has "never been done before".
The Titanic director said: "Basically, whenever you add water to any problem, it just gets 10 times harder. So, we've thrown a lot of horsepower, innovation, imagination and new technology at the problem, and it's taken us about a year and a half now to work out how we're going to do it."
Cameron confirmed that the majority of underwater scenes will take place in Avatar 2 and 3. Release dates for the sequels have been set for December 2020 and December 2021.
Titanic star Kate Winslet has been confirmed in the cast, alongside Sam Worthington, Zoe Saldana, Sigourney Weaver and Stephen Lang.