Prince William and Kate Middleton have been pronounced man and wife at Westminster Abbey, BBC reports.

Miss Middleton is wearing an ivory and lace gown designed by Sarah Burton at Alexander McQueen.

Some 1,900 guests watched the couple exchange their vows, with many millions watching at home.

Thousands of people are lining the procession route the couple will take to Buckingham Palace after the wedding.

The service has run smoothly so far but there was a tiny moment of drama as the prince struggled to place the wedding ring on Miss Middleton's finger. Following a long tradition, the ring has been fashioned from Welsh gold given to Prince William by the Queen.

After the couple said their vows, in which she did not promise to obey William, the Archbishop of Canterbury, the Most Reverend Rowan Williams, declared: "I pronounce that they be man and wife together, in the name of the Father, and of the Son, and of the Holy Ghost. Amen."

The prince is wearing the red tunic of an Irish Guards colonel - his most senior honorary appointment.

Prince William has been given the title of the Duke of Cambridge by the Queen, and Miss Middleton will become Her Royal Highness the Duchess of Cambridge on their marriage.

The prince has also became the Earl of Strathearn and Baron Carrickfergus, which means Miss Middleton will become the Countess of Strathearn and Baroness Carrickfergus.

Well-known faces have been spotted at Westminster Abbey, including singer-songwriter Sir Elton John and his partner David Furnish, former England rugby coach Sir Clive Woodward, and former England football captain David Beckham and his wife Victoria.

Actor Rowan Atkinson, a close friend of Prince Charles, Prince Harry's friend Chelsy Davy and film director Guy Ritchie have also arrived.

UK Prime Minister David Cameron and his wife Samantha, Australian prime minister Julia Gillard, former British PM Sir John Major, and current Home Secretary Theresa May are among the politicians present. Mr Cameron did not cause an etiquette upset and wore a morning suit despite initially suggesting he might not.

BBC reporters at the scene estimated between 3,000-5,000 people had been camping overnight in the Mall and around Westminster Abbey.