The hit series, which tells the story of a bickering mother and daughter from Melbourne, ran from 2002 until 2008.
The show's stars Gina Riley and Jane Turner sparked rumours of a movie project last year (10) when they were spotted at the Sydney Film Festival, and now the pair has confirmed the project.
And they have landed a big screen star to help boost the film - British actor Richard E. Grant has agreed to appear.
Riley says, "We sent Richard the script and he came back and said, 'I would love to be a part of it.' We love him. He is perfect for Kath & Kim."
Shooting starts in Italy next month (Sep11).