Updated

"Late Show" host Stephen Colbert was reportedly sent a legal notice by lawyers of Rose Hanbury, the Marchioness of Cholmondeley, whom the CBS star recently joked about having an unsubstantiated affair with Prince William. 

"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 attorneys told In Touch Weekly on Thursday. "We have written on our client’s behalf to CBS and various other reputable media organisations to confirm that the allegation is false."

Representatives for Paramount and Hanbury did not immediately respond to Fox News Digital's requests for comment. 

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Rose Hanbury

Rose Hanbury, Marchioness of Cholmondeley, sent a legal notice through her lawyers to "Late Show" host Stephen Colbert over jokes he made about her over an alleged affair with Prince Williams, which she has repeatedly denied.

On the March 12 installment of "The Late Show," Colbert made a joke at Hanbury's expense while addressing speculation about Kate Middleton. 

"The kingdom has been all a flutter by the seeming disappearance of Kate Middleton. Well now, internet sleuths are guessing that Kate’s absence may be related to her husband and the future King of England William having an affair," Colbert told his audience. "So, I think we all know who the alleged other woman. Say it with me –– the Marchioness of Cholmondeley –– what a beautiful name!"

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Mentioning how the rumors first surfaced in 2019, Colbert continued, "According to tabloids back then, when Kate supposedly confronted him about it, he laughed it off saying 'there was nothing to it.' Aha! Always a good response when your wife accuses you of cheating. ‘Ha ha, imagine me having an affair!' It is to laugh," using a British accent.

Stephen Colbert jokes about Rose Hanbury

"Late Show" host Stephen Colbert elevated unsubstantiated rumors about an affair involving Prince Williams during his March 12 monologue. (Screenshot/CBS)

After weeks of conjecture about her absence from the public following abdominal surgery, the Princess of Wales revealed on Friday she had been diagnosed with cancer.

"I wanted to take this opportunity to say thank you, personally, for all the wonderful messages of support and for your understanding whilst I have been recovering from surgery," Middleton said in the video recorded Wednesday.

"It has been an incredibly tough couple of months for our entire family, but I’ve had a fantastic medical team who have taken great care of me, for which I am so grateful," she added.

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Princess Catherine smiles

Kate Middleton, the Princess of Wales, revealed she had been diagnosed with cancer and is undergoing chemotherapy.  (Paul Grover/Pool/AFP via Getty Images)

"The Princess will return to official duties when she is cleared to do so by her medical team," a Kensington Palace spokesperson told Fox News Digital. "She is in good spirits and is focused on making a full recovery."

The Princess of Wales, 42, explained that after her abdominal surgery, it was believed her condition was "non-cancerous." However, further testing showed "cancer had been present." She was advised to begin chemotherapy by her medical team.

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"This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family," she continued. "As you can imagine, this has taken time. It has taken me time to recover from major surgery in order to start my treatment. But, most importantly, it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be ok."

"As I have said to them; I am well and getting stronger every day by focusing on the things that will help me heal; in my mind, body and spirits," Middleton added. "Having William by my side is a great source of comfort and reassurance too. As is the love, support and kindness that has been shown by so many of you. It means so much to us both."

Fox News' Lauryn Overhultz contributed to this report.