Kate Middleton and Prince William were ’forced’ to confirm their relationship during....

Kate Middleton and Prince William had tried their best to keep their romantic life away from the spotlight for a long time. However, their attempts fell short at a dinner party where the duo was forced to admit their love affair due to a drinking game.

According to royal biographer Robert Jobson's new book, 'Catherine, the Princess of Wales', the couple had attended a dinner party with their friends when those in attendance decided to participate in the popular drinking game 'Never Have I Ever'.

It was one of Princess of Wales' ex-girlfriends, Carly Massy-Birth, who revealed that Prince William was dating Kate Middleton during the confession-like drinking game, said Jobson in his book.

In his biography, Jobson, according to People, wrote: "Perhaps unwittingly, Carly exposed William’s secret love affair with Catherine, much to the prince’s chagrin."

Royal biographer Katie Nicholl too had made the same claim in her 2002 book 'The Making of a Royal Romance'.

"She announced, 'I’ve never dated two people in this room,’ knowing full well that William was the only one who had because Kate was sitting next to him," a source who attended the party told the author before adding that every single one of the party guests was "in shock."

The same source alleged that in response, Prince William shot his ex-girlfriend a "thunderous look" before whispering under his breath: "I can't believe you just said that."

"We knew they were together," the source continued at the time, "but it was the first time William confirmed his and Kate’s relationship in public."

The royal couple first encountered each other in 2001 at St. Andrews University in Scotland. Popular rumors suggest that William captivated Middleton by purchasing a £200 front-row seat to observe his future wife on the runway at a charity fashion show.