Kevin Costner is demanding a judge toss a sexual harassment lawsuit filed against him by a stunt performer who claims she was forced to participate in an unscripted and unscheduled rape scene on the set of the Western film series, “Horizon.”

According to new court docs … Costner says Devyn LaBella was happy as a clam during the film shoot he directed, and she even sent a text to a supervisor that she had a great time after the whole thing wrapped.

Per the docs … LaBella texted, “Thank you for these wonderful weeks! I so appreciate you! I learned so much and thank you again. I’m really happy it worked out the way it did too. Have a great rest of the shoot and yes talk soon!”

Costner and his cast and crew also filed a bunch of declarations refuting LaBella’s narrative … with Kevin’s pitbull lawyers, Marty Singer and T. Wayne Harman, adding, “There was no anger or resentment, only enthusiasm and gratitude” at the end of filming … so what changed?

According to Costner’s declaration, everything was on the up and up so nothing should have changed. Here’s Kevin’s version of the events …

On the day in question, LaBella — the stunt double for actress Ella Hunt — was shooting a scene with actor Roger Ivens in a covered wagon. The two were lying next to each other and LaBella was fully clothed in an ankle-length dress with bike shorts underneath. Ivens raised the hem of her dress and swung his leg over her body, ending up on all fours above her. But that’s it. There was NO nudity, rape, simulated sex or physical contact between LaBella and Ivens.

Costner goes on to say while LaBella’s dress may have gotten bunched up at her knees, the gown was always below her waist and the pantaloons and petticoats underneath remained undisturbed.

Bottom line, Kevin insists there’s was NO violent rape scene on his set. Period!