It has long been known that the 19 year-old Diana Spencer was wracked with such doubts on the eve of her marriage to Prince Charles that she told her sisters, “I can’t marry him, I can’t do this, this is absolutely unbelievable” (only to be told it was too late to change her mind because her face was already printed on the tea towels), but now a new biography of Prince Charles claims that Charles harbored similar doubts, telling an aide on the eve of his wedding: “I can’t go through with it.”According to a report in The Telegraph, Catherine Mayer, whose unauthorised biography Charles: Heart of a King is to be published on Thursday, quotes a member of the Prince’s inner circle as saying that on the eve of the wedding in 1981 the Prince “was desperate” as he had belatedly realised Diana was “not the jolly country girl he had assumed.”He is said to have told his confidant: “I can’t go through with it…I can’t do it.”But, says Mayer: “She had no idea her bridegroom also had to be coaxed to the altar.”Prince Charles's office has responded to the book by claiming Mayer overstated the exclusive access she was given to the Prince,but Mayer told the BBC: “I had some help from Clarence House to not only attend events that press could accredit for, but also to talk to members of his inner circle and his friends.”