Both director Lasse Hallström and actor Josh Gad have expressed concern over an on-set video from the production of their upcoming film “A Dog’s Purpose,” showing a frightened German shepherd trying desperately not to be placed in a studio tank of rushing white-water rapids — followed by panicked moments after the dog appears to go under.

Gad, 35, who voices the central animal’s thoughts in the live-action film and was never on set, tweeted that he had “signed on for a film that truly stands out as one of the most beautiful love letters to animals I have ever seen. Today, however, I saw a disturbing video that appears to show a scared German Shepherd being forced to perform a stunt on the set of this film. … I am shaken and sad to see any animal put in a situation against its will.”

He added, “As a proud dog owner and a fervent supporter of organizations like PETA, I have reached out to the production team and studio to ask for an explanation.”

Three-time Oscar-nominee Hallström, 70, whose films include “What’s Eating Gilbert Grape” and “The Cider House Rules,” tweeted that he was “very disturbed by the video” and “did not witness these actions.” He said, “I have been promised that a thorough investigation into this situation is underway and that any wrongdoing will be reported and punished.” It is generally second-unit directors who film stunts and other footage not involving primary actors.

The organization that ensures animal safety in film and television productions said Wednesday it is investigating whether a frightened dog was forced into churning water during the making of “A Dog’s Purpose.”

American Humane has also suspended its safety representative who worked on the film and is hiring an independent investigator to explore the matter, said Mark Stubis, a spokesman for the organization.

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The animal-welfare organization People for the Ethical Treatment of Animals (PETA), after seeing the minute-long video posted Wednesday by TMZ.com, called for a boycott of the film, alleging on its website that the company supplying the dogs in the film has a problematic record, and that, “Sadly, such abuse appears to be the norm, not the exception, in the entertainment industry….”

In a joint statement, production company Amblin Entertainment and distributor Universal Pictures assured that Hercules, the dog in the video, “is happy and healthy.” Saying the crew “followed rigorous protocols to foster an ethical and safe environment for the animals,” they stated that, “ On the day of the shoot, Hercules did not want to perform the stunt portrayed on the tape so the Amblin production team did not proceed with filming that shot.” They said they would “continue to review the circumstances shown in the edited footage.”

The movie opens Jan. 27.