Sigourney Weaver’s allergy worries

Sigourney Weaver became worried she would be recast on the movie due to her allergies.

Early into filming, the actress was concerned that she was allergic to the ship's cat Jones, which she feared would lead to her being recast.

Luckily, Sigourney’s rashes were traced back to the glycerine spray that was being used to give the illusion that Ripley was sweating.

The spray was changed, and the actress was able to stay on the project.