It's not unusual to have a side hustle, but most people don’t moonlight as pilots—or for that matter, serve as monarchs by day. But as The Guardian reports, King Willem-Alexander of the Netherlands has spent the past two decades secretly juggling his royal duties with commercial airline gigs.

In an interview with Dutch newspaper De Telegraaf, King Willem-Alexander revealed his part-time job to the public, announcing that he temporarily abdicated his duties as a bi-monthly “guest pilot” for Dutch airline KLM so he could learn to operate a Boeing 737. Before his 21-year stint with KLM, the royal worked for Martinair, another national airline.

As a co-pilot for KLM, King Willem-Alexander helped operate flights twice a month, for both the government and the KLM Cityhopper service, according to BBC News. The royal told De Telegraaf that an airplane's cockpit serves as an escape from the throne: “You have an aircraft, passengers and crew. You have responsibility for them. You can't take your problems from the ground into the skies. You can completely disengage and concentrate on something else. That, for me, is the most relaxing part of flying.”

The Dutch people knew that King Willem-Alexander was a licensed pilot, and that he operated the occasional KLM aircraft. That said, they didn’t know how often he did it—and most of the time, passengers didn’t even notice the king’s presence behind closed cockpit doors, or recognize his voice over the intercom. (“Most people don’t listen anyway,” he told De Telegraaf.)

King Willem-Alexander operated KLM’s fleet of smaller Fokker 70 planes, but he’ll have to learn to fly Boeing 737s now that the former aircrafts are being discontinued. The 50-year-old king plans to continue flying—and as Europe’s youngest monarch, he’ll likely soar the friendly skies for years to come.

[h/t The Guardian]