London, Aug 21 : Prince William's girlfriend Kate Middleton and Prince Harry's ladylove Chelsy Davy have been invited by the Queen to Buckingham Palace for Prince Charles's 60th birthday, it has emerged.

Kate and Chelsy will be among more than 150 guests at the lavish banquet.

But Kate, 26, and Chelsy, 22, must adhere to the strict dress code of "long dresses".

Wills, 26, and brother Harry, 23, will be kitted out in black tie.

The party takes place on November 13, the day before Prince Charles's birthday.

Sources expect a string of dignitaries to attend - such as PM Gordon Brown.

The invitation to a formal reception at Buckingham Palace represents a first for Kate and Chelsy.

"It would have been a snub to William and Harry to have left their girlfriends' names off the guest list," The Sun quoted a source, as saying.

It is understood a televised concert celebrating Charles's life is planned for the same week.

ANI