Times when an actor or actress didn't quite know what movie they were making?

The Thin Red Line, the movie was shot to center around Adrien Brodys character, he did interviews about his starring role and photoshoots and all the press that comes with being the star. He was told during the premiere that Terrence Malick had changed the entire movie during editing to focus on Jim Caviezels character.

Olivia Newton-John said Xanadu's script kept being rewritten on the hoof while they were filming.

As others have said, one of the reasons Gina Gershon is such good, campy fun in SHOWGIRLS is because she is the only one of the leads who understands exactly the kind of movie she's making. Poor Elizabeth Berkley and the others seem to have no idea.

Scooby-Doo the first live action movie was meant to be something similar to the Brady Bunch movie where it pocked fun at the show and its stoner elements and Velma and Daphne were going to be sexalized, but then it was changed after the cast signed up, some elements of that stuff are in the movie but way toned down.

When John Cusack saw the final cut of Better Off Dead (1985), he got pissed and accused the director of "tricking him."

Bette in Wicked Stepmother. Poor thing thought it would revive her career.

The Avengers

Piper Laurie thought Carrie was a black comedy and that her character was too over-the-top to be taken seriously.

[quote]Olivia Newton-John said Xanadu's script kept being rewritten on the hoof while they were filming.

When I met Olivia Newton-John while she was filming Xanadu she told me it was a "roller disco movie".

The little boy in The Shining had no idea the subject matter of the film. He was completely shielded and clueless.

Renee Zellweger’s hammy, hillbilly making turn in Cold Mountain owns this thread. She was in a completely different movie than everybody else. I thought this Oscar win was confusing and just a fluke. Then she wins for another mediocre performance and without Weinstein too.

Pretty sure Malcolm McDowell and Sir John Gielgud didn't realize that Caligula was going to have inserts added that made it hardcore porn.

I think many of the actors who appeared in films directed by George Lucas qualify, he's notorious for giving his actors no direction at all. Anyone who's appears in one of his films while being young and inexperienced is going to spend the whole time going "Wait a minute, what am I supposed to do?", and that tells you everything you need to know about Hayden Christiansen in the prequels. Or Jake Lloyd.

Piper Laurie has said that when she auditioned for [italic]Carrie,[/italic] she thought it was a comedy.

In The Usual Suspects Gabriel Byrne worked his scenes believing his character was Keyser Söze

When actress Suzanne Shepherd showed up for the table read of [italic]A Dirty Shame,[/italic] she was so horrified by the subject matter that she broke down crying and John Waters had to beg her not to leave.

Ahem...

[quote]Piper Laurie has said that when she auditioned for Carrie, she thought it was a comedy.

Piper Laurie didn't audition for Carrie, Brian Depalma asked her to do it outright but she did think it was a comedy because her dialogue was so over the top..

Pretty sure the cast of Cats (movie) had no idea what was happening.

Any of Andy Warhol’s movies.