The actress, who has voiced the ogress in all four instalments of the Shrek franchise, has said that she would have rid herself of her Californian accent had she known that the character's parents were being voiced by Julie Andrews and John Cleese.
The 37-year-old told About.com: "If I had known that Fiona's parents both had British accents when I first started, that they were being voiced by Julie Andrews and John Cleese, I might have because when I first started the movie, when I did my voice, I didn't know who was playing my parents.
"So it was one of those things where I was like, 'Wait a second! How come I sound like I am from California?'"
Shrek Forever After is currently playing in US cinemas and is released in the UK on July 2.
