Lady Rose Hanbury, who was rumored to have a past affair with Prince William, reportedly sent a legal notice to Stephen Colbert after he made a joke about the pair during a recent episode of his CBS late-night show.On the March 12 edition of the “Late Show,” Colbert, 59, trolled Marchioness of Cholmondeley, 40, and the Prince of Wales, 41, about the 2019 rumors.Even more, he speculated they were still dating amid Kate Middleton’s recent abdominal surgery recovery.“The rumor appears to have entered into the mainstream media recently as a result of another joke made about it on ‘The Late Show with Stephen Colbert,’” Hanbury’s lawyers said in a statement to In Touch.The memo continued: “We have written on our client’s behalf to CBS and various other reputable media organizations to confirm that the allegation is false.”The Post has reached out to Colbert for comment. Middleton, 42, has been recuperating from her procedure that she underwent in January.