Dutch Prince Friso, brain-damaged and in a coma after being caught in an avalanche eight months ago, was showing some signs of improvement, the palace said Monday.
"Recently Prince Friso has been showing small signs of consciousness. This condition is referred to as 'minimal consciousness'," the palace said in a statement.
"The prognosis however remains very uncertain and the medical team is still very worried," the palace added.
"It will still take many months before there is any clarity on his condition," it said.
Friso, 44, was transferred to London's Wellington Hospital in March from Austria after being buried by an avalanche on February 17.
Doctors at the time said Friso may never regain consciousness.
The father of two, the second son of Queen Beatrix, was skiing off piste in the Lech resort with a friend when the avalanche struck.
At the time the avalanche alert level was at the second highest, meaning there was a particular risk away from the prepared ski slopes.
The Dutch royal family had been vacationing in Lech, where it regularly spends its skiing holiday, when the accident happened, and members of the family made daily visits to the prince's bedside in Innsbruck before his transfer.
Prince Friso has been chief financial director of Britain's URENCO group -- dealing with nuclear fuel supplies -- since 2011, and previously worked with the investment bank Goldman Sachs in London.