When she joined him at the altar, Prince William whispered to his bride and a smile crept across her face.
Kate Middleton's nerves appeared to disappear as the future king of England, known for his sense of humour, comforted the newest member of the royal family.
The couple, now the Duke and Duchess of Cambridge, had started the procession back to Buckingham Palace in the 1902 State Landau, for their balcony appearance.
The thunderous clouds that threatened to give way to rain held off for the newlyweds and the rest of the royal family as they were escorted by the Household Cavalry.
During the service, the couple couldn't take their eyes off one another as they gave their vows in front of millions around the world.
There were a few stifled laughs as William struggled to fit the wedding ring over her finger.
The band was made from a piece of Welsh gold gifted to William shortly after the couple's engagement.
Kate reportedly had to have her engagement ring, the sapphire first given to Princess Diana by Prince Charles, resized as she lost weight before her big day.
The bride looked immaculate in her highly anticipated lace wedding dress, with two-metre train, hand made by Sarah Burton of Alexander McQueen.
With some of her hair pulled off her face, Kate wore a Cartier tiara, lent to her by the Queen.
The heavily jewelled piece was purchased in 1936 by the Duke of York for his Duchess, Queen Elizabeth - later the Queen Mother - and presented to Princess Elizabeth, now the Queen, on her 18th birthday.
The tiara was paired with Robinson Pelham diamond earrings, given to Catherine by her parents.
Her modest bouquet was made up of five different flowers - lily-of-the-valley, sweet william, hyacinth, ivy and myrtle.
Commissioned in all three armed services, Prince William dressed in his Irish Guards Colonel uniform for the ceremony.
Draped over his scarlet tunic was a gold and crimson sash with the wings of the Royal Air Force, the Garter Star and the Golden Jubilee medal.
He wore a forage cap he left at the Great West Door of the Abbey on arrival.
William and Kate were married in less than 15 minutes.
They then took a seat near the Queen, Prince Philip and William's best man Prince Harry at the High Altar to listen to the rest of the hour-long service.
Kate's party-planner parents, Carole and Michael Middleton, sat across from them, beaming. They were joined by her brother James, who delivered a reading, and sister Pippa, Kate's Maid of Honour, who also wore Alexander McQueen.
The couple signed three registers and the marriage certificate in private in the chapel of St Edward.
The Bishop of London, Richard Chartres, offered the couple some words of advice in his sermon.
He said husband and wife "make one another their work of art" but must also give one another "space and freedom".
"Many are full of fear for the future of today's world but the message of the celebrations in this country and far beyond its shores is the right one - this is a joyful day.
"It is good that people in every continent are able to share in the celebrations because this is as every wedding day should be."
It was as if Mother Nature held off the threatening rain especially for the grand occasion, allowing the entire wedding to pass without a drop. The black clouds threatened to give way to thunderous rain all morning but held off for the wedding.
Earlier, Kate brought hysteria to the crowds as she waved and smiled along the procession route from Buckingham Palace to the Abbey.
She and her father were greeted in their 1960s Rolls Royce Phantom VI by her sister who carried her train into the church.
Watching a piece of history unfold, the crowds - 15 people deep in some places - from around the world held signs of congratulations, many dressed up as if they were attending the ceremony themselves.
Tents were packed up along The Mall, in front of Buckingham Palace, and opposite the Abbey, to make for standing-room-only crowds.
Fans clambered up on fences and brought ladders to try and get a glimpse of the royal family.
The city was a sea of red and blue with every second person waving a Union Jack flag.
Huge cheers rang out before the royal family started their procession when forklifts and street sweepers drove past.
A carnival atmosphere had been created at Trafalgar Square, just off the procession route where a large screen streaming all the action had been erected.
People young and old dressed up in wedding attire or opted for memorabilia T-shirts with the couple's face on them. Some wore masks of William and Kate's faces.
Thousands also gathered at Hyde Park, many having picnics or bringing blankets with cheese and wine.
Police were out in force, lined up along the procession rote and checking bags at road blocks, wary that the event was a massive terrorist threat.
Guests started arriving in buses at the Great North Door of the Abbey, three hours before the ceremony was due to begin.
Victoria Beckham, seen entering the church with her husband David, was in a black dress and black, sparkly fascinator with her hair pulled back in a pony-tail.
British socialite and good friend of the couple, Tara-Palmer Tomkinson, was seen entering the church in a bright blue dress and matching hat and gloves.