Munster Go Home! (1966) featuring Debbie Watson.
“Even as “The Munsters” was being canceled in 1966 by CBS, the producers and Universal were still going through with a motion picture as planned for the Munsters. Pat Priest was oddly replaced by Universal contract player Debbie Watson as Marilyn.” Munsterland.
“Q: Why is there yet a third actress, Debbie Watson, playing Marilyn in the movie “Munster, Go Home”? Priest: Well, that broke my heart. As they were preparing to make that movie, they came down on the set to tell me that I wasn’t going to be doing it. They came on the SET to tell me. Very sensitive, right? (I’m being facetious. No, not sensitive at ALL!) They said they felt I was too old. Al and Fred went to bat for me, but it didn’t work. Q: You weren’t too old for the show but you were too old for the movie? Priest: Debbie Watson was under contract to the producers and they were paying her, so they just wanted to use this gal they had under contract. It was all a matter of money. They’d have had to pay me more than they’d have to pay her.” Monster Kid Classic Horrror Forum.