Prince William and Kate Middleton should be "left alone" and allowed to "get on with their lives", Tony Blair has told the BBC.
There had been rumours of an engagement
The prime minister told BBC One's Politics Show that most of the media coverage about the couple's split would turn out to be "complete nonsense".
Speculation has been mounting about why the prince and Miss Middleton recently ended their four-year relationship.
The break-up was examined in great detail in the Sunday newspapers.
Mr Blair said the announcement about the ending of the couple's relationship should now end the issue.
"They should be left alone now without reams of stuff being written that I can assure you, from my experience of royal stories, most of which will be complete nonsense," he said.
"I think, now it has been announced, they should be allowed to get on with their lives."
He said much of what was bad about being in the public eye was media reporting that was either unfair or untrue.
"My experience of it actually is that what concerns people is not so much the invasion of their privacy as such, because I think most people in public life accept that you are bound to be a public issue and item in that sense," he said.
"I think it is more that usually whatever is discussed about you publicly is surrounded by a whole lot of other stuff that is either unfair or sometimes completely untrue and that is the thing that really gets people down."
The break-up was examined in great detail in the Sunday newspapers, although there was little agreement on the reasons for the split of the couple who met at St Andrews University, Fife, in 2001.
Theories included the prince's Army career, his party lifestyle and interference from the Royal Family.
Miss Middleton's career and the views of her family have also been cited as causes.
It has been suggested that the 24-year-old prince's move to an army camp in Dorset, and Miss Middleton, 25, continuing her life in London, may have put a strain on the relationship.
While Liberal Democrat president Simon Hughes blamed the intense media pressure on Miss Middleton as a factor in the split.
BBC royal correspondent Peter Hunt said Prince Phillip and the Queen may well have advised Prince William to act so as not to leave Miss Middleton "hanging out to dry" if there was no prospect of marriage.
Clarence House has not yet commented on the break-up.