AceShowbiz - Potential "Dune" audience may need to be prepared for a major letdown when they watch the movie this coming fall. A lucky fan, who got to watch the film earlier during a test screening, has detailed scenes of the upcoming pic, confirming speculation about the concerningly "abrupt" ending.

[SPOILER ALERT!] According to the so-called legitimate source who spoke to Twitter account @SecretsofDune, the ending makes it clear that "there must be a sequel." The leaker further spills that the movie ends "abruptly" after Paul (Timothee Chalamet) fights Jamis (Babs Olusanmokun).

In the novel, the fight between Paul and Jamis, a Fremen whom Paul is tasked with defeating in order to get himself and his exiled mother Lady Jessica (Rebecca Ferguson (II)) into the good graces of the Fremen people, takes place a little halfway through the book. If the movie does end with this fight, fans surely will hope the rest of the book will be addressed in a sequel, which has not been greenlit yet.

However, it is widely believed that there are two different versions of the movie which have been shown at the test screenings. @SecretsofDune thinks that the actual movie will not end with the Paul vs. Jamis fight, but with the Water of Life ceremony, in which Paul is proven to be the fabled "Kwisatz Haderach."

"I just feel that the Water of Life scene is a natural ending," the Twitter account, which so far has become a trusted source of "Dune" news, tells Inverse. "It feels right. It's also at the end of Book II, just before the time jump in the 'Dune' story."

Of why Warner Bros. showed the abrupt ending to some fans at the test screenings, the account manager theorizes it's "perhaps an effort by WB to determine which ending suits a general audience best."

To confirm which ending does make the final cut, fans have to watch "Dune" when it opens in theaters across the nation on October 1.