Joan Rivers sparked outrage with a "disgusting" joke about Princess Diana.
The 79-year-old comedienne shocked TV guests including Cat Deeley during filming of a British special of her show 'Fashion Police' when she made a "tasteless" jibe about the princess, who died in a Paris car crash in 1997.
Speaking about Duchess Catherine - who was known as Kate Middleton before she married Diana's eldest son Prince William - Joan said: "If you ever want to go to Paris, fly don't take the tunnel."
One stunned viewer slammed the "vicious" jibe.
Andrew Henry told the Daily Star newspaper: "It was tasteless to Kate and especially vicious to her husband William.
"There are plenty of other subjects to make fun about in a show about fashion. But that was one step too far. Cruel, vicious and disgusting.
"Diana was also an icon across the globe. Her charity work was revered and her death was tragic."
Despite her comments, Joan is good friends with Diana's ex-husband Prince Charles and his current wife Camilla, Duchess of Cornwall.
She said recently: "I stayed at the Ritz - as usual - when I went to Prince Charles's wedding to Camilla. I met him through a friend at a charity event and just adored him from the start. I adore Camilla too.
"Humour was the connection from the beginning. I don't pretend to be on the short list, though, if you know what I'm saying. I probably see them twice a year."