American tourists once met the Queen and had no idea who she was so she played a joke on them

• The Queen once met American tourists who didn't recognize her while walking around her holiday home.
• She was with Richard Griffin, a royal cop at the time, and told the tourists he'd met the Queen.

$4 at the age of 96. She had an unprecedented $4, which was filled with historic moments and delightful memories.

And one sweet anecdote, from former Royal Protection Officer Richard Griffin, sheds light on $4.

Speaking to $4, Griffin revealed that the Queen once played a prank on two American tourists who didn't recognize her.

Griffin said he and the Queen came across the American hikers one day while they were walking around the grounds of $4

—Jake Kanter (@Jake_Kanter) $4

"There were two hikers coming towards us, and the Queen would always stop and say hello," Griffin said. "And it was clear from the moment we first stopped that they hadn't recognized the Queen."

Griffin said one of the Americans began telling the Queen where they came from and what sites they had seen in Great Britain. Then he asked the Queen where she lived.

"She said, 'Well I live in London, but I've got a holiday home just on the other side of the hills,"' Griffin recalled. "And he said, 'How often have you been coming up here?'"

When the Queen told the American she had been coming up to Balmoral Castle for over 80 years, the hiker asked if she had ever met Queen Elizabeth.

"Well I haven't, but Dick here meets her regularly," the Queen replied, referring to Griffin.

The hiker then turned to Griffin and asked: "Oh, you've met the Queen? What's she like?"

"Because I was with her a long time and I knew I could pull her leg, I said, 'Oh, she can be very cantankerous at times, but she's got a lovely sense of humor,"' Griffin told Sky News.

The American then put his shoulder around Griffin, got his camera out, and gave it to the Queen, asking if she could snap a picture of him with the royal protection officer.

"Anyway, we swapped places and I took a picture of them with the Queen and we never let on and we waved goodbye," Griffin said. "And Her Majesty said to me, 'I'd love to be a fly on the wall when he shows those photographs to their friends in America — and hopefully someone tells him who I am.'"

Those who know the Queen wouldn't be surprised by the story, as she has a reputation for $4.