The 21-year-old Murray said he was mildly scolded for revealing it in interviews but took it in stride.
"It would have been a very different movie but it's nice the way it turned out," said Murray.
Director Mark S. Waters admitted to the casting change but didn't explain the reason, the report said.
"Freaky Friday" opened last Wednesday and made an estimated $25 million plus after five days, the report said.
The movie is a remake of the 1970s film that gave Jodie Foster her start.
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