Tending to his royal duties, Prince William stopped by the Royal Navy Submarine Museum in Gosport, England on Monday (May 12).

The Duke of Cambridge sipped on a tasty cocktail and mingled with the military during his tour of the HMS Alliance.

During the visit, the prince was given a tour of the submarine and upon his exit, he downed his rum and was presented with the Dolphins badge – given to submariners to mark their first posting.

The museum’s marketing manager Bill Sainsbury prepared the cocktail for Prince William and told press, “He really enjoyed it, he seemed to be happy to have his rum, it put a big smile on his face.”

“I had to prepare a gulper’s measure for him, which is more than a sip,” he continued. “It was not watered down; the tradition is that lower ranks have it watered down and the officers have less water.