When Prince William was a young man he had a variety of interests but one hobby, in particular, would leave his grandmother, Queen Elizabeth II so worried, she often feared for his life.

Prior to having children with his wife Kate Middleton, William often road motorcycles at speeds as high as 177 mph, which made members of the royal family fear he would never get the chance to take the throne.

In the documentary “Chasing the Royals,” royal photographer James Whitaker noted William picked up the dangerous hobby despite its connections to his mother, Princess Diana’s past. “I think it frightens the life out of people at Buckingham Palace and almost certainly, the Queen too.”

“It is a strange thing. His mother was constantly fleeing from the paparazzi, who were on motorbikes. Now her son is using a motorbike for the same sort of reasons,” Whitaker added.

The Duke of Cambridge previously admitted he got a rush from his dangerous motorcycle riding sessions.

“I don’t know what it is about bikes, but I’ve always had a passion for motorbikes ever since I was very small. I used to do a lot of go-karting when I was younger and then after that, I went on to quad bikes and eventually motorbikes,” William explained.

However, once Kate gave birth to Prince George, Princess Charlotte and Prince Louis, Prince William realized it was time to give up his dangerous hobby to ensure he would be around to support his family.

Queen Elizabeth and Prince William Queen Elizabeth II worried about Prince William. The Duke of Cambridge is pictured during “The Patron’s Lunch” celebrations for The Queen’s 90th birthday on June 12, 2016 in London, England. Photo: Jeff Spicer/Getty Images