David Cronenberg met with some opposition when he announced that he wanted to cast Jeff Goldblum in the lead role of "The Fly" (1986). The executive at Fox who was supervising the project felt that Goldblum was not a bankable star, and Chris Walas felt that his face would be difficult to work with for the make-up effects. Both, however, deferred to Cronenberg's judgment.
Cronenberg himself later had reservations when Goldblum suggested Geena Davis, his girlfriend at the time, for the other lead role, as he did not want to have to work with a real-life couple. Cronenberg was convinced after Davis's first reading that she was right for the role. Producer Stuart Cornfeld suggested that they audition more actresses, saying that it's the "script that is brilliant." Cornfeld relented after "nobody else even came close."
It's been reported that initially creature effects designer Chris Walas felt Jeff Goldblum's face would be difficult to work with, makeup wise. Stating, "David asked if there was anything specific he should be looking for when he was casting Brundle. We told him to try and find someone with a small bridge of the nose to allow us more freedom with the make-up. Jeff's got a larger nose and big ears that were a bit of an issue to deal with, but when David said he was thinking about Jeff for the role, both Stephan and I were very enthusiastic and said we'd make it work. We were both fans of Jeff's work."
Davis wasn't acting when Goldblum's right ear falls off. Her reaction in the film was genuine and she was genuinely shocked when it was filmed and Cronenberg kept the take of her reaction in the film.
In a 1987 interview on "Sinister Image" Vincent Price (from the 1958 original) revealed that when this remake was released, Goldblum wrote him a letter saying, "I hope you like it as much as I liked yours." Price was touched by the letter, he composed a reply and went to see the film, which he described as "wonderful, right up to a certain point... it went a little too far." (IMDb)