New Zealand will literally turn blue for the Prince of Cambridge. Major landmarks in the country will glow in blue lights on Tuesday night in celebration of the birth of Prince William and Kate Middleton's baby boy.

Catherine, Duchess of Cambridge, or simply Kate to the rest of the world, has just given birth to a son on Monday, July 22, at 4.24pm, London time. The as-yet unnamed baby has bumped his uncle, Prince Harry, as the third in line to the UK thrones and its Commonwealth realms.

New Zealand, as one of the 16 Commonwealth realms, is just as excited as the rest of the world about the future king's birth. And to honour the famous newborn's arrival, 37 enlisted landmarks in the country will be bathed in blue lights.

Royalist group Monarchy New Zealand had had a team of volunteers on high alert by their phones as they waited for the official announcement from the palace. They were ready to call the managers and caretakers of the landmarks throughout the country to light them in the right colour, which would have been pink if the Duchess had given birth to a girl.

As it happened, the landmarks will now be lighted in blue.

Group Chairman Sean Palmer said that the list of 24 participating landmarks expanded after he heard from other organisations that wanted to join the celebration.

"This is the first time in over a century that a monarch of New Zealand has lived to see three direct heirs," Dr Palmer was quoted by the 3 News as saying.

"If this baby is as long-lived as his great-grandmother, Queen Elizabeth II, he will be on the throne when the 22nd century begins."

Included in the celebration are the Sky Tower, The Cloud, and Holy Trinity Cathedral in Auckland.

Mr Palmer added going blue will be good for New Zealand, saying, "Free media coverage displaying some of our national landmarks is bound to be good for our image abroad and our tourism at home."

Meanwhile, Prime Minister John Key has congratulated the royal couple on the birth of their son with a shawl. New Zealand's official gift to William and Kate is a hand-spun shawl that is similar to the shawl the country gave when William was born.

It is designed by Margaret Stove, who also designed the previous shawl, while Cynthis Read spun the wool and knitted the shawl.

"New Zealanders remember with fondness the visit of Prince William when he was just a toddler, playing on the lawn of Government House with a Buzzy Bee. It would be a great pleasure to welcome Prince William's son to New Zealand as well," Mr Key said.

Aside from the lighting of the prominent landmarks in the country, New Zealand will also celebrate the birth of the Prince of Cambridge by firing a 21 gun salute from Point Jerningham, Wellington on Tuesday.

Related:

Royal Baby Watch: Kate Middleton Delivers a Bouncing Baby Boy, The Future King of England [Read]

Royal Baby News: Celebrities Tweet Their Congratulations [Read]

Feature: Prince William-Kate Middleton 'Royal Baby Cambridge' Breaks History as the World Rejoices for the Third King in Waiting [Read]