A photograph of Prince William posted on his website revealed his nickname "Big Willy" inscribed on a mug he owns, the Deccan Herald reported.
The photograph of the royal, part of a set published by St. James' Palace on the prince's website, showed his nickname on a mug at Royal Air Force Valley on Anglesey, north Wales. An edited version of the photograph, where the mug was cropped out, was issued in November but a new version with the cup in the background is now visible on Prince William's website.
The image was first editing in November as a security measure when the Ministry of Defense saw classified information visible in earlier photos of Prince William, which resulted in them having to reset dozens of user names and computer passwords of Royal Air Force (RAF) staff.
The caption on the cropped photograph said, "The Duke of Cambridge making a cup of tea whilst working as a helicopter search and rescue pilot at RAF Valley on Anglesey, Wales."
It was added that the picture, which was undated, was part of a "day in the life" set of photos featuring Prince William flying RAF Sea King helicopters as a Search and Rescue pilot.
Prince William's mother, the late Princess Diana, reportedly called her son "Willy Wombat" while he was a child and he also went by "Wills," a name used by family and friends.
Prince Williams calls his wife, Duchess of Cambridge Kate Middleton, "Babykins" and she revealed during a visit to her childhood school that her nickname was once "Squeak," according to The Christian Post.
"I was nicknamed Squeak just like my guinea pig. There was one called Pip and one called Squeak because my sister was called Pippa and I was Squeak," she told students at St. Andrews.
St. James' Palace announced in December that Middleton is expecting the couple's first child and they added on Monday that she is due to give birth in July.