Kate Middleton

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File this under things that will never happen: A Kate Middleton and Prince William sex tape!

But Vivid Entertainment, the world's leading distributor of celebrity sex tapes, is dreaming big, announcing Dec. 30 that the royal couple top the 2013 list of celebrity twosome they'd like to see star in an X-rated film.

Kate, 31, and William, also 31, have actually been Vivid Entertainment's top choice to make a celebrity sex tape for the past three years. Steven Hirsch, the company's founder/co-chairman, said in a statement that in the past year, "Kate's pregnancy and birth to Prince George only made the couple more popular," explaining, "They project natural good looks and good health and their stature on the world stage is unparalleled."

"We know our chances of getting them to star in a sex tape are slim," added the Vivid exec, "but that's what wish lists are for." (You might recall that Vivid Entertainment previously offered Prince Harry $10 million to star in an adult film after his infamous naked pics in Las Vegas surfaced and Pippa Middleton could've banked $5 million for a sex tape after the release of her underwear and bra photos leaked. Obviously, neither Harry nor Pippa took Vivid Entertainment up on these offers.)

But, um, commoners, keep on dreaming, these aren't likely to come to light. Vivid Entertainment's other top couples they want to capture in the act also seem unlikely. Katy Perry and John Mayer are the sex tape producer's second choice to make a movie, followed by Beyoncé and Jay Z as their third.

Cringe de la cringe.