Bosses apparently want to bring in a fourth judge to join Simon Cowell and Amanda Holden, who are confirmed for the new series, and David Walliams, who is expected to sign up.
Womack is said to have flew out to Los Angeles last week for a meeting with Cowell, but now 55-year-old Cattrall has emerged as a rival for her position.
A source said: "We love Kim. She might be best known for her American TV shows but she was born in Liverpool and spent a lot of time here in Britain."
Meanwhile, producers are also considering moving Britain's Got Talent from Fountain Studios in Wembley to Pinewood Studios as they strive to ensure the new series is a success.
The source added: "Some of the new acts are on such a grand scale that we are considering moving to a bigger studio. We want the show to return to its former glory."
Fountain is currently home to all of Cowell's shows, including The X Factor and Red or Black?
Britain's Got Talent returns to ITV1 next Spring.