Olivia Colman's husband stole a loo roll from Buckingham Palace.

The 'Crown' actress and her spouse Ed Sinclair - with whom she has three children - met Prince William at a charity event at the royal residence and not only was the Oscar-winning star ''uncool'' when she spoke to the prince, the couple were determined to bag a souvenir to mark the occasion, however small.

Asked if she's had approval from t he royal family since landing her role as Queen Elizabeth in the Netflix drama, she said: ''''Since getting the part, I've met the Queen in a line-up at the BFI, and the lovely Prince William at a charity do at the palace.

''I was very uncool, and he was charming. He has that thing where he makes you feel you're the most exciting person in the room...

''Then my husband stole some loo roll just to say we got it from Buckingham Palace. If we can get away with that, we can get away with this programme.''

During her brief encounter with the prince, William insisted he doesn't watch the drama series based on the life of his family.

She recalled: ''He said, 'I know what you're doing here.' I asked, 'Do you watch it?' He said, 'No, I don't.' ''

The 45-year-old actress admitted she is ''completely obsessed'' with the queen because she's grown to realise how ''extraordinary'' she is and what a great presence she has been in people's lives.

She told the Sunday Times magazine: ''The thing is, I was always a republican, but I have to say I've become completely obsessed with the Queen.

''I've become a lefty monarchist, and there's not many of them about. Who could stick with something like that for so long, quietly and with such humility?

'' We know she loves to escape to the Highlands. She probably goes crazy up there -- she must release in some way, running around naked, screaming and pulling her hair out.

''The Queen is an extraordinary human being. However you feel about her, she's been our constant. We are all so relaxed about her being there that one day, when she's not, it's going to be a shock.''