The birth of the Royal baby boy to Prince William and Kate Middleton means that three direct-descendant heirs are alive during a British monarch's reign for the first time since 1894.
The newborn will be third in line after grandfather Prince Charles and father Prince William.
And if he lives to the Queen Elizabeth II's current age of 87, he could well be on the throne in 2100, as Britain's first monarch of the 22nd century, the Sun reported.
The last time the monarch met her great-grandson was when Queen Victoria was alive at the same time as her son Edward, her grandson George and his son Edward.
They went on to become Edward VII, George V and Edward VIII, the report said.
Baby Cambridge's place in the line of succession was assured irrespective of gender because of changes to royal rules this year.
The Succession to the Crown Act, given royal assent on April 25, means first-born daughters will no longer be snubbed in favour of younger sons.
The old law saw Princes Andrew and Edward and their kids leapfrog older sister Princess Anne.
But the new statute cannot come into force until it is adopted by all 15 of the other Commonwealth states who have the Queen as their head of state.
That could take between six months and a year, the report said.
However, the legislation will not yet be needed because the new arrival is male and will be Wills' and Kate's eldest child.