Fans got a surprise Monday on HBO Max.

The highly anticipated "Justice League" director's cut by Zack Synder, aka the #SnyderCut, accidentally leaked on the streaming service. 

According to reports, when some fans selected to watch the new "Tom & Jerry" movie the re-edited DC Comic movie started instead.

One user told Variety that he was able to watch an hour of "Justice League" before it cut out. 

HBO Max confirmed the accidental leak to Fox News in a statement. 

"Zack Snyder’s Justice League was temporarily available on HBO Max, and the error was addressed within minutes," a spokesman for the company said. 

ZACK SNYDER'S 'JUSTICE LEAGUE' TRAILER RELEASED BY HBO MAX FEATURING NEVER-BEFORE-SEEN FOOTAGE

(L-R) Henry Cavill as Superman, Jason Momoa as Aquaman, Gal Gadot as Wonder Woman, Ezra Miller as The Flash, Ben Affleck as Batman, and Ray Fisher as Cyborg.

(L-R) Henry Cavill as Superman, Jason Momoa as Aquaman, Gal Gadot as Wonder Woman, Ezra Miller as The Flash, Ben Affleck as Batman, and Ray Fisher as Cyborg. (HBO Max )

Synder's version of the superhero film features Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ray Fisher as Cyborg, and Ezra Miller as The Flash.

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The film was originally released in 2017 to mediocre box office success and poor reviews after director Joss Whedon took over in post-production because Synder stepped away due to the tragic death of his daughter.

Whedon conducted extensive reshoots and rewrites which left many fans aching for the original Synder version. 

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After years of rumors, Synder's four-hour version drops Thursday, March 18.