The Archbishop of Canterbury will marry Prince Harry and Meghan Markle, Kensington Palace announced today.

Justin Welby will officiate over the couple's vows at St George's Chapel, Windsor, on Saturday, May 19, after saying their decision to marry 'before God' in a church was based on a 'seriousness both about faith and about their lives together'.

The service will start at midday and at 1pm the couple will tour through Windsor in a carriage, greeting well-wishers who are expected to come from all over the world to line the streets. The timing of the service will allay fears over a clash with the FA Cup final, which is expected to kick off later in the afternoon.

The Rt Rev David Conner, dean of Windsor, will conduct the service at St George's Chapel, with Welby presiding over the vows themselves. Kensington Palace did not say who would give the address. 

Markle, 36, who is a Protestant Christian and went to a Catholic high school, will be baptised before the service and also intends to become a British citizen. It is not clear whether Welby will oversee her baptism service as well.

She, along with Prince Harry, will receive a new title to signify their marriage.

The couple, who are planning the wedding themselves, said they hope to 'share their celebrations with the public'.

In a series of updates about the day Kensington Palace said the couple will leave Windsor Castle by carriage, travel via Castle Hill, along the High Street and through Windsor Town before returning along the Long Walk for their reception.

'They hope this short journey will provide an opportunity for more people to come together around Windsor and to enjoy the atmosphere of this special day,' a spokesman said.

They will return for a reception with guests of the service before a second reception for friends and family later in the evening.

'Prince Harry and Ms Meghan Markle are hugely grateful for the many good wishes they have received since announcing their engagement,' a spokesman said.

'They are very much looking forward to the day and to being able to share their celebrations with the public.'

St George's Chapel, Windsor, which is where Prince Charles and the Duchess of Cornwall's marriage was blessed by Rowan Williams, the former Archbishop of Canterbury, is a more intimate setting than alternatives such as St Paul's Cathedral or Westminster Abbey, where the Duke and Duchess of Cambridge's married. It holds 800 people and is the favoured location of Harry and Meghan. 

Welby previously said he was 'absolutely delighted' by the news of their engagement.

'I have met Prince Harry on a number of occasions and have always been struck by his commitment and passion for his charities, and his immense love for his family,' he said in a statement from Lambeth Palace.

'Marriage is a special and joyous commitment, one that Jesus celebrated together with friends at the wedding in Cana. I am so happy that Prince Harry and Ms Markle have chosen to make their vows before God.

'I am very, very sure after conversations that this is no tick-box exercise,' he later told the BBC's Today programme.

'There is a profound sense of commitment, seriousness both about faith and about their lives together which is quite inspirational.'

He added: 'It is important because people look at it and they will see a model of how two people commit their lives to one another before God and in the presence of millions of people.'