They are related through a distant tudor relative. Apparently.

Wills and Kate, kissing cousins! How the Royal lovebirds are related thanks to a Tudor tyrant so bloodthirsty he's been airbrushed from history

Read more: http://www.dailymail.co.uk/femail/article-1299794/How-Prince-William-Kate-Middleton-related-thanks-Tudor-tyrant.html#ixzz1KjPc5E4J