Prince William and Prince Harry ''don't mess'' with their grandmother.
The young royals revealed that they are especially careful not to upset their relative Queen Elizabeth in a television interview.
Speaking in an ABC special programme title 'The Real Queen By Her Own Royal Family', the princes revealed they are just like any other grandchildren.
Harry, 27, said: ''Behind closed doors, she's our grandmother, it's as simple as that.''
Meanwhile, 29-year-old William, who recently enjoyed his first wedding anniversary to Kate Middleton admitted they had realized she is not a soft touch as youngsters.
He said: ''As I learned from growing up, you don't mess with your grandmother.''
Harry also joked with host Katie Couric that Prince Charles' mother hadn't even requested his friendship on social networking website Facebook.
He replied to her humorous question: ''No she hasn't. Why has she friended you?''
The sons of the late Princess Diana recorded the rare interview on the grounds of Buckingham Palace to mark the Queen's Diamond Jubilee events this year.
The full show is due to air in the United States on May 29 at 9/8c.