Back in1997, Chris Farley was originally going to be the voice of Shrek, but the gig eventually went to Mike Myers, as Farley died later that year and didn’t get to finish his lines (said to be about 80-90% completed).
Above you can check out recently released storyboards and voice-over featuring Chris Farley as Shrek with Eddie Murphy as Donkey.
The Skrek movie was released in 2001 with Myers using a Scottish accent.