'Screamboat' Star Assures Worried Disney Fans Slasher Film Won't Ruin Mickey Mouse

Disney fans have nothing to worry about ... 'cause the upcoming horror flick based on "Steamboat Willie" is not going to undo any of Mickey's magic, says a star of "Screamboat."

Here's the deal ... the ultra-bloody indie horror movie takes the OG Mickey Mouse character and drops him in a slasher film -- all thanks to the character now being in the public domain.

Tyler Posey, who stars in "Screamboat," tells TMZ ... there is nothing for Mouseketeers to worry about ... 'cause the the killer rodent in his movie is clearly not Mickey.

TP is sure Disney fans will be able to clearly see a major difference between his bloodthirsty puppet costar and the beloved children's character, without any blurred lines.

As TMZ previously reported ... "Screamboat" was filmed entirely on Pete Davidson and Colin Jost's decommissioned Staten Island Ferry ... and our sources tell us so much fake blood was used during filming they had to hire a special cleaning crew.

TMZ obtained some photos from filming ... and you can see a puppeteer setting up Screamboat Willie on different parts of the ship. They began filming in May and wrapped over the summer.

"Screamboat" also stars David Howard Thornton from the 'Terrifier' series as Screamboat Willie ... the film will be coming out in 2025.