The 67-year-old actress said she was hesitant about starring in the 1979 fantasy thriller, in which she portrays Ellen Ripley, because she thought it was a "bleak script", reported Femalefirst.
"It was a very, very bleak script," she told the Sydney Morning Herald.
The star was even more disappointed that she has graduated from Yale School of Drama to be cast in the franchise.
"I survived drama school to do this?" she added.
It was not until Weaver spoke to director Ridley Scott that she had a change of heart, and realised the movie was going to be completely different to what she had initially thought.