LONDON (REUTERS) - After arriving to a global media frenzy, Britain's Prince George will make his second official appearance this week at a christening designed to be as low-key as possible for the world's most-hyped baby.

Prince George, third-in-line to the British throne, will be christened on Oct 23 in a private, 45-minute ceremony in the Chapel Royal at St James' Palace by the spiritual leader of the Church of England, the Archbishop of Canterbury Justin Welby. The prince will become the formal head of the Church of England himself if he accedes to the throne.

Few were surprised by Prince William and his wife Kate's decision to break with tradition and not hold the service in Buckingham Palace as is typical for royal christenings. The royal couple, known as the Duke and Duchess of Cambridge since their 2011 wedding, have made it clear they are not sticklers for tradition and their informality has helped portray a more modern, relevant royal family in austerity-hit Britain. So far, the only official photographs of Prince George are family snapshots taken by Kate's father Michael Middleton.

The christening will be the first time in over 100 years that four generations of royals are photographed together, with a picture of Queen Elizabeth, her son and heir Prince Charles, Prince William and Prince George to be released after the event.

Although the christening will be held behind closed doors, tourists and well-wishers have already flocked to the 16th century St James' Palace built by Henry VIII in central London.

"In the States, the royals fascinate people, especially William and Kate who are young and approachable," said Mr Sean Tyrrell, 44, a policeman from Manteca, California, outside the palace gate flanked by guards in red tunics and bearskin hats.

German students Julia Magrian and Anne Krause, both aged 17, said they would be following the christening closely, keen to see what Princess Kate wears. The "Kate-effect" is well-known, with anything the duchess wears prompting a sales rush.

"We like Kate because she is a link between royalty and the common people and she has great style," said Ms Magrian.

Royal officials have released few details before the christening, allowing only one photographer and one TV crew inside the palace - unlike Prince George's birth when an army of cameramen camped outside St Mary's Hospital for three weeks.