Context: Princess Fiona is a fictional main character who serves as the female lead in DreamWorks' animated Shrek film series. She made her first appearance in the first film in the franchise, Shrek (2001), voiced by American actress Cameron Diaz.

Question: who does the voice of fiona in shrek?
Steam of consciousness below:

To answer this question, we should know that: She made her first appearance in the first film in the franchise, Shrek (2001), voiced by American actress Cameron Diaz.
So, the answer is American actress Cameron Diaz.