Kate Middleton was thrown aback by Prince William ex-gilrfriend

Kate Middleton was once put off by one of Prince William's ex-girlfriends during a game of 'Never Have I Ever' in college.

The Duke and Duchess of Cambridge, who started dating secretly in 2003, kept their courtship under wraps for the longest time to avoid public attention.

Royal author Katie Nicholl tells OK! Magazine that during this time, Kate was made uncomfortable by the Duke's ex-girlfriend Carly Massy-Birch.

At a college party, William and Kate along with Carly and a bunch of other friends sat down to play a round of Never Have I Ever, where the former girlfriend made the Duke spill about his relationship with the Duchess.

“When it was Carly’s turn to play, 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.

“He shot Carly a thunderous look and said under his breath, ‘I can’t believe you just said that’ before drinking his shot.

“Kate didn’t speak to Carly much after that, but we were in shock.

“We knew that they were together, but it was the first time William confirmed his and Kate’s relationship.”

In addition to the brave move, Kate was often irritated by Carly over her closeness to William.

“She could literally wave to William from her sitting room, where she would sit knitting by the window, which rather grated on Kate.”