A group of production assistants are going after behemoth Paramount, claiming they were forced to take dumps in their cars while working on some of the studio’s highest-grossing blockbusters.

The class action lawsuit was filed by 4 NYC based P.A.s, who say they began working for the studio in 2010 and put in mega hours for films like ‘TMNT,’ ‘Wolf of Wall Street,’ “Noah,” and “Transformers: Dark Side of the Moon,” which grossed more than $1 billion.

The group — assigned to keep location shoots clear of pedestrians and cars — claims they regularly put in 60-100 hours a week but never got overtime pay.

It gets worse … they say they weren’t allowed to leave their posts to get food or use the restrooms. Some say it was so bad they had to urinate and defecate into bottles and buckets in their cars.

We reached out to Paramount, so far no word back.