Dame Helen Mirren wrote letter to the Queen while playing her in 2006 film

Helen Mirren playing Queen Elizabeth II in the film The Queen (PA)

Dame Helen Mirren has spoken of her relief that she sent a letter to the Queen while she was shooting her 2006 film about the monarch.

The drama, written by The Crown creator Peter Morgan, focused on the death of Diana, Princess of Wales, and whether the Queen would return to London from Balmoral to pay tribute amid growing public pressure.