A source told the newspaper, "The Duke wasn’t just watching from the sidelines. He was fully immersed at times on undercover surveillance operations, not just sitting in front of a computer in an office.
"He impressed everyone with his professionalism… He spent most of his time with ordinary rank and file workers, not just the bosses, and sat with them in the canteen to join in their discussion."
Wills, 36, started his duties at MI6, the Secret Intelligence Service, in March.
Another source said of the 36-year-old heir to the throne, "He feels it’s very important as future king that he followed up from his time in the military to find out as much as possible and understand the role played by people working to defend us here at home."
Responding to the report, William paid tribute to his grandmother’s spies. "Spending time inside our security and intelligence agencies, understanding more about the vital contribution they make to our national security, was a truly humbling experience.
"These agencies are full of people from everyday backgrounds doing the most extraordinary work to keep us safe."
The Duke added, "They work in secret, often not even able to tell their family and friends about the work they do or the stresses they face."
Move over, Daniel Craig. Make way for Wills!