THE Queen has opened up about the literal weight of responsibility that comes with being the head of the monarchy — and wearing the crown.

In a rare conversation with Alastair Bruce, an expert on the Crown Jewels, Queen Elizabeth II reveals she is afraid of looking down while she’s wearing one of the crowns because it could break her neck.

“You have to keep your head very still,” Bruce reportedly says as the pair examine the Imperial State Crown and watch footage of the Queen’s Coronation in 1953.

“Yes,” the Queen agreed. “And you can’t look down to read the speech you have to take the speech up.

“Because if you did your neck would break, it would fall off.

“So there are some disadvantages to crowns, but otherwise they’re quite important things.”

According to UK’s The Telegraph, the footage is shown as part of an hour-long BBC One documentary The Coronation which airs in the UK this weekend and features behind-the-scenes footage of the Queen, capturing her sense of humour and life in the palace.

The Queen wore the Imperial State Crown following her coronation and often wears it when she reads the Queen's Speech during the State Opening of Parliament.

One of the scenes shows the Queen describing the crown, which weighs almost 10kg, as “very unwieldy”, to which Bruce adds: “It’s difficult to always remember that diamonds are stones and so they’re very heavy.”

After succeeding the throne after the death of her father George VI, the Queen explains how she had the crown adjusted to make it more feminine and smaller.

“Fortunately my father and I have about the same sort of shaped head. But once you put it on it stays. I mean it just remains on,” she said.

Bruce told reporters at a press screening of the documentary that the Queen seemed very at ease with the Crown Jewels, even grabbing a table the crown was resting and dragging it closer.

“She said, ‘Well, you know, it’s my crown,’” he said.

“She was very practical with the Crown Jewels in a way I wasn’t quite expecting.”

The Queen also reveals the Gold State Coach is “not very comfortable” and features footage of her speaking about her mischievous children and a dress so heavy she got stuck on the carpet.