Queen Elizabeth II has rarely been seen dancing, but there is a special rule that even bans her from doing it at the Royal Albert Hall.

According to a report in The Mirror, the British royals including the monarch are officially banned from dancing at the Royal Albert Hall because of a rule written in a 150-year-old document. Craig Hassall, CEO of the Hall, revealed, "It's in the constitution, you are not allowed."

The rule states that one cannot dance in the Royal Box that is occupied by members of the royal family and their esteemed guests. However, there was one instance where it seemed that the Queen herself was on the verge of breaking the rule.

The incident happened when the Queen was attending a concert with Nelson Mandela in 1996. The former South African president was in the United Kingdom on a four-day state visit and an event, titled "Two Nations Celebrate," was held at the Royal Albert Hall in his honour.

The event featured a number of spectacular performances, including those by Phil Collins, Tony Bennett, and Quincy Jones. The Queen and her son Prince Charles were joined by Mandela and his daughter Zenani Mandela-Dlamini in the Royal Box as the event raised cash for Charles's charity.

Artistic Director Lucy Noble recently told the RocknRoll Business podcast that the power-packed performances left everyone in the audience dancing, but unfortunately, the royals couldn't let themselves forget the protocols. Their guests were also not supposed to dance because they were in the royal box, but Mandela couldn't stop himself from busting a few moves.

Noble recalled, "The entire Royal Family were here in the Queen's box with Nelson Mandela. It was a complete party atmosphere – the whole Royal Albert hall was up dancing. But there is this policy in the Queen's box that you can't dance. They were all sat there."

"But Nelson Mandela gets up and does this really cool dancing," he added.

After her guest broke into a dance, it appeared that the monarch was also finding it too hard not to sway along. Noble recounted, "Then the Queen stood up and held her handbag and just stood there. It was hilarious, that moment."

Royal Variety Performance
Britain's Queen Elizabeth arrives at the Royal Variety Performance at the Royal Albert Hall in London in 2012. REUTERS