Princess Diana
Princess Diana drove a submarine in 1986. Pictured: Princess Diana wearing a Jasper Conran suit during a visit to a community centre in Brixton, October 1983. Getty Images/Princess Diana Archive

Princess Diana’s surprising reaction upon seeing a poster of half-naked women in the submarine has just been revealed.

In the YouTube documentary “Charles: The Destiny of a Prince,” it was revealed that Princess Diana embarked on a solo royal trip and was apprehensive because she didn’t have Prince Charles by her side.

On Aug. 22, 1986, she boarded a nuclear-powered submarine and ignored the traditional British naval superstition that the presence of a woman on a warship could bring bad luck. Princess Diana wore a light blue sweater and pale blue dungarees during the outing.

She reportedly stayed aboard for four hours as the submarine sailed beneath the waters of the Clyde, off the Scottish coast. Upon entering the submarine, Princess Diana’s attention was captured by a poster of two half-naked women on the interior of the submarine.

Princess Diana asked the naval officers who were the two women in the poster, but they couldn’t give her an answer. The mom of two once again asked the men who the poster belonged to and they all laughed because no one wanted to answer her question.

Meanwhile, Princess Diana had the opportunity to take the helm at the wheel and drive the submarine through the Scottish coast. The HMS Trafalgar sailed to the Scottish naval base of Faslane and a helicopter whisked Princess Diana to Balmoral Castle, one of the residences of the royal family in Scotland.

Following her time aboard the submarine, a royal spokesperson said that Princess Diana had a wonderful time.

“There is an old superstition, dating to the time of Admiral Nelson, which says the presence of a woman aboard warships brings bad luck. This presumably dates to the time when officers took their mistresses to sea with them,” the source said.

The presence of a woman aboard the submarine reportedly distracted the men from doing their duties. However, Princess Diana ignored the superstition and made the most out of her trip without Prince Charles.

At that time, Prince Charles was also out sailing the Scottish seas but on a separate royal visit.