The Simpsons: The Movie writer Al Jean is glad the animated series has taken almost 20 years to make it's big screen, because it would have disappointed its fans if it was made any earlier.

The hit animated comedy was created by Matt Groening in 1989 and parodies clueless father Homer, his wife Marge and their three children Lisa, Bart and Maggie.

The Emmy award winning show aired its 400th episode this month, but the makers are only now ready to bring The Simpsons to Hollywood - and Jean insists it was the right choice.

He tells British film magazine Empire: "We couldn't do it before 2001, as we didn't have the voice cast signed. If we had done it ten years ago we wouldn't have had the ability to do the animation that we have now. We couldn't have made this film five years ago."