London: Prince Harry, who went on a charity trip to the Arctic earlier this year, kept the visit secret from his grandmother Queen Elizabeth as he believed she would think he was "completely mad". (Agencies)
The 26-year-old Harry took part in the "Walking With The Wounded" trek in April in which he battled sub-zero temperatures, a leading English daily reports.
He has said in a BBC documentary titled "Harry's Arctic Heroes" that his father Prince Charles was nervous about the trip.
"My father obviously knew I was coming out here and so did my brother. But I kind of kept it quiet - I don't know why it happened - so my grandparents and the rest of my family probably just found out about it and they probably think I'm completely mad. It's probably right," Harry said.
The expedition to the North Pole was undertaken by a team of wounded British soldiers - who were injured fighting in Afghanistan. The team covered over 250 km in 12 days. Harry joined them in the early days of the walk - just before his brother William's wedding.
He had spent some time preparing for the trek on the Norwegian island of Svalbard.
"My father was very nervous because of the lack of training that I've done and quite rightly so, he's got a lot of friends who have done this, he's got professional opinions that no doubt would have advised him saying 'do not let your son go'."
The prince also reflects on his varying roles as a soldier and a royal.
"I think I have three different lives - one's my military life, one's my private life and one's the sort of public stuff. But, you know, me as a military man is probably my number one favourite because you get to some time with people like this - it is very special."
London: Prince Harry, who went on a charity trip to the Arctic earlier this year, kept the visit secret from his grandmother Queen Elizabeth as he believed she would think he was "completely mad".