Greta Gerwig has said she won't criticise her films in case it ruins the viewing experience for fans.
The Frances Ha star appeared in rom-com Arthur with Russell Brand, who has since said he felt he made a mistake by taking on the film.
Greta said: "Sometimes the experience of making a movie is so different from what a movie actually is and sometimes they're disconnected, you can have a wonderful time making a movie and it turns out the movie's c***. Or vice versa, you can have a terrible time and it's a great movie.
"I certainly see the movies and have opinions on them, but I don't like to pass judgment because the one time I did it and said I don't like this movie I did, someone I really love said, 'That was my favourite one,' and I was like I shouldn't have said anything because it's taking away the experience of what they had with it.
"It doesn't matter what I think about it, I'm in it, if someone liked it I don't want to invalidate their liking it."
But Greta said Russell's feelings about Arthur hadn't changed how much she liked him.
She said: "It's interesting Russell said that. I love Russell, he's so great. I saw him in LA recently, he saw me across the room and he was like, 'Greta you nerd, what are you doing?' I was like, 'Russell!' He just makes fun of me more than anyone else."
Frances Ha is out in cinemas now.