Sigourney Weaver says 'Avatar 2' will start filming in fall

April 4 (UPI) -- Avatar 2 star Sigourney Weaver says the long-delayed movie will start filming in the fall.

The 67-year-old actress, who played Dr. Grace Augustine in the original 2009 film, promised in an interview with The Hollywood Reporter that the sequel will be "well worth" the wait.

"We're starting!" Weaver said Monday at a New York screening of The Assignment. "We're starting training, and we're starting -- hmm, I probably can't say anything. "We will be actually shooting it by the fall."

Avatar was directed by James Cameron, and earned $2.7 billion at the box office. Cameron will also helm the sequel, which was initially expected to premiere in 2014, but has been pushed back year after year.

"I'm telling you, these scripts are so amazing, I'm not worried about [disappointing fans] at all," Weaver said. "Am I worried about how we're going to bring them to life? Yes, because they're so ambitious."

"They're so worth it," she assured fans. "They're well worth waiting for. I'm not worried about that at all. We're trying to get it done as quickly as possible."

Cameron confirmed plans in April 2016 for four more Avatar movies -- Avatar 2, Avatar 3, Avatar 4 and Avatar 5 -- that will "form a complete saga." He told the Toronto Sun in March that Avatar 2 had once again been pushed back.

"Well, 2018 is not happening. We haven't announced a firm release date," the director said.