His title is Duke of Cambridge, but Prince William was a real-life knight in shining armor for a pair of teenage sisters in England.

William, 30, was working his day job as a search-and-rescue pilot in the Royal Air Force (RAF) Thursday afternoon when a call came in that a 16-year-old girl had been swept out to sea off the coast of Silver Bay in Anglesey.

From Crib to Captain: Prince William Through the Years

The girl, who has not been identified, and her 13-year-old sister had been body-boarding in the water when they were caught on a riptide, according to the BBC. As the girl tried to help her younger sister, she also became distressed.

While the younger sister was able to be pulled safely to shore by onlookers, the 16-year-old remained stranded in the water.

Less than 38 seconds after receiving a distress call, an RAF rescue helicopter captained by Prince William came to her rescue.

PHOTOS: William and Kate Celebrate the London Olympics

With the aid of two surfers waving and pointing to the area where the girl was stranded, William swooped the helicopter down to the waters while his winchman, Master Aircrew Harry Harrison, pulled the older sister out of the water.

"When I got to her, the elder girl was clearly exhausted and was going under the water for what was the very last time," Harrison told the BBC. "We never know what we'll face when we're called out, this was one rescue where we truly did arrive in the nick of time and managed to save two young lives."

Both sisters were taken to a nearby hospital as a precautionary measure but were said to have suffered from only the shock and cold of the water.

There was no word on whether the 16-year-old realized the famous pilot behind her rescue, but the RAF said she thanked Harrison on the way to the hospital for saving her, according to the BBC.

Prince William became an RAF search-and-rescue captain in May. His No. 22 Squadron is based in Anglesey, close to where the rescue took place and where he and wife, Kate Middleton, have set up home.

William was forced to miss the Closing Ceremony of the London Olympics, leaving his wife and brother, Prince Harry to fulfill his official role, because of his RAF duties.