Austen, who died in 1817, penned the classic romances "Pride and Prejudice," "Sense & Sensibility," "Emma," "Mansfield Park," "Persuasion" and "Northanger Abbey," many of which have inspired popular film adaptations.
Middleton married Prince William in April in a ceremony watched by millions all over the world.
People.com said historians for the genealogy Web site found Middleton and Austen are 11th cousins, six times removed.
"Finding this connection between the Duchess of Cambridge and Jane Austen is very exciting since, in many ways, Catherine is the modern Jane Austen heroine: a middle-class girl marrying the future King of England," People.com quoted lead historian Anastasia Harman as saying Tuesday. "Jane Austen may have written about happily-ever-after, but it seems Catherine has found a non-fiction hero to spend her life with -- far past the epilogue."