Nearly 30 years on from her death, the funny, mischievous, complex and troubled personality of Diana – the other Princess of Wales – still shines bright. Newly released letters written by the princess to one of the great heartthrobs of the day, the actor Terence Stamp, illustrate perfectly the woman I came to know in the 1990s.

At the start of the decade, when these letters were penned in Diana’s bold, round handwriting, she and Charles were still acting out the charade of a fairytale marriage. In reality, their relationship had fallen apart and they were both involved in extramarital affairs. To the outside world, however, she remained the perfect princess, a global star and future queen.

Diana always had an eye for a handsome face, and Terence Stamp was devilishly good-looking. The two of them clearly had a close friendship. Right up until his death last year, he maintained it was platonic. We shall never know the truth, but what does it matter?

What is true is that Diana needed friends she could confide in, have fun with – and let her naughty side escape for a while. They often had lunch together; sometimes he cooked. She sent him a card showing a couple in bed with the caption: “Why did God invent sex?“ Inside it said: “So that married people do something at least twice a year.”