Archbishop's biggest fears about the royal wedding

Britain's Prince Harry and Meghan Markle leave after attending the Commonwealth Service at Westminster Abbey in London. Photo / AP

The Archbishop of Canterbury today revealed Meghan Markle's baptism into the Church of England was a "very special, beautiful and sincere" ceremony.

Justin Welby said the service at St James's Palace in London - also attended by the US actress's fiancé Prince Harry - was "very moving" and a "great privilege".

But he joked that he must "not drop the ring" at their wedding at Windsor Castle on May 19, adding that he was also keen to ensure he gets "the vows in the right order".

Dr Welby, 62, conducted the intimate 45-minute baptism service at the Chapel Royal on March 6, with Prince Charles and the Duchess of Cornwall also present, reports Daily Mail.

The service to formally introduce her into the Anglican faith marked an important step on her transformation into future granddaughter-in-law to the Queen.

Dr Welby was asked what he could say about the service – at which neither Prince William nor the Queen were present - by ITV News presenter Julie Etchingham.

He replied: "Almost nothing at all. Except that it was very special, it was beautiful and sincere. And very moving. It was a great privilege."

Justin Welby says it was a "great privilege" to conduct St James's Palace service. Photo / Getty Images

Meghan had asked Dr Welby to lead the service after forming a close bond with him in recent weeks as he instructed her on the rites and sacraments of the Church.

Speaking about the royal wedding, the Archbishop added: "Unlike recent weddings, I must not drop the ring! And I must not forget to get the vows in the right order as I did at the rehearsal for one of my children's weddings.

"At the heart of it is two people who have fallen in love with each other, who have committed their lives to each other with the most beautiful words and profound thoughts, who do it in the presence of God, through Jesus Christ.

"You pray for them to have the strength to fulfil their vows. And you seek to do it in a way that respects their integrity and honours their commitment."

The royal wedding service will be conducted by the Dean of Windsor, David Connor, with the Archbishop presiding as the couple make their vows.