Chris Farley was the American comedian who acted as Shrek’s original voice while the film was being made in 1997, 4 years before the finished film actually came out.
Unfortunately, Farley died of a drug overdose before he could complete the project. It has been suggested that he had completed as much as 90% of the dialogue for the film.
As you know, Shrek ultimately became an enormous franchise thanks to Mike Myers and his odd-but-apt Scottish interpretation of the character. Myers and Farley had worked together on a number of occasions, including episodes of Saturday Night Live and Wayne’s World 2.
Click on the video if you’d like to hear Shrek’s original voice.