DIANA & CATHERINE
Parallels exist between Diana and Catherine -- with both women being beautiful and glamorous and getting a lot of media attention, but the media presentation of Catherine is more developed than Diana.
However, the biggest difference may be that very weighty expectations were placed on Diana's shoulders from the very beginning.
While a lot is expected of Catherine, there is also a realization that the demands of media and duty played a part in her early death in a car crash fleeing paparazzi in Paris in 1997.
Diana's first pregnancy was announced in November 1981, just over three months after her wedding to Prince Charles in St Paul's Cathedral in London.
Diana gave birth in June 1982 to Prince William at the same St Mary's Hospital, Paddington, which Catherine was admitted to.
Charles was 34 by this time, and there had been mounting calls in the media during the 1970s for him to get married.
His marriage and the swift birth of Prince William afterwards meant that the British royal family now had a successor to the throne that reached for two generations.
William is 32, but there was less pressure on him to get married, and less on Catherine to get pregnant than there had been with Diana.
Public and media felt there were still two generations of the Royal family waiting to succeed to the throne before it would be the turn of any of William's children.
Both mothers-to-be suffered mishaps during the pregnancy. Diana fell down the stairs at the country home of Queen Elizabeth II at Sandringham, while Catherine suffered morning sickness.
But it is the differences in the circumstances of the marriage and of their backgrounds and characters that stand out.
Catherine had a kind of apprenticeship to the role of royal wife with a long period as William's girlfriend.
This gave her chance to decide if she really wanted to be a royal duchess, with experience of the media and of the royal family and life from the inside.
Catherine had also been to university and came from a stable family background. And she was older than Diana when she married -- 29 to Diana's 19.
Diana came from a broken home, where her parents had divorced and fought a bitter custody battle over her and her brother and sisters.