The waxworks museum plans to arrange a sitting for Prince William's new bride after their wedding next year.
And with the world-famous creations taking four months to complete, the tourist attraction said a dummy Kate Middleton could be unveiled towards the end of 2011.
She would join models of the Queen, the Duke of Edinburgh, the Prince of Wales and the Duchess of Cornwall, and Princes William and Harry.
A spokeswoman for Madame Tussauds said: "We have a really good relationship with the Royals and they always do sittings for us.
"It looks likely it will be shortly after the wedding and then it takes four months to complete."
There were no clues as to how Miss Middleton might appear.
"It depends on what she wants and whether she can donate clothing," the spokeswoman added.
The attraction said it had not yet discussed whether to create waxworks of Zara Phillips and Mike Tindall, the latest Royal couple to get engaged.