OSLO -- Norway's Crown Princess Mette-Marit is asking Norwegian media to leave her oldest son alone.

Mette-Marit says Marius Borg Hoiby, her son from a previous relationship who has no royal title or official duties, has in recent years "been exposed to pressure" from some media "that I don't feel is worthy of them."

He "is not a public person," she added.

Norway's future queen made headlines in 2001 when she married Crown Prince Haakon, because she was a single mother who had lived a freewheeling life with a companion with drug offence conviction.

The royal website posted the open letter a day before Borg Hoiby' 20th birthday Friday. He lives with the popular royal couple and their two children, and now plans to travel abroad like many young Norwegians.