Will Prince William and Kate kiss on the balcony?
Until July 29, 1981, no newly-wed royal couple had kissed in public, but after Prince Charles and Lady Diana responded to a chorus from an ecstatic public and kissed on the balcony of Buckingham Palace on that heady day, they started a whole new royal tradition.
Prince William and Kate can be expected to dutifully follow suit on Friday.
The young couple will not only bear the weight of traditions going back centuries, but also reflect the ethos of modern times.
For centuries, royal weddings were private events that took place in palaces and castles like Windsor.
The most recent royal wedding was that of Prince Charles and Camilla Parker-Bowles, on April 9, 2005.
Unlike his first marriage to Lady Diana, this was a low key event at the Windsor castle, a civil ceremony followed by religious blessing.
There was none of the pomp and pageantry that the world witnessed on July 29, 1981.
This time there were no horse driven carriages; the couple arrived in a glass car, while Princes William and Harry arrived in a mini-bus.
If Prince Charles' second marriage was an understated event, sensitive to public mood, his youngest brother Prince Edward had a similar low key event in Windsor when he married Sophie Rhys-Jones on June 19, 1999.
According to Fiona Macdonald, author of 'Royal weddings: A very peculiar history,' modern royal weddings in the past 90-odd years marked a significant break with the past.
"Until the 19th Century and early in the 1900s, the pattern had been largely the same for the past 1,000 years. Royal weddings were usually arranged for political, dynastic and empire-building reasons, and the bride and groom were always of mutually royal rank," she says.
Marrying a commoner was exceptionally rare, but on April 26, 1923, Prince Albert married Elizabeth Bowes-Lyon, mother of the present Queen Elizabeth.
Some royal weddings were held during difficult times.
King George ensured that the 1923 wedding of Prince Albert became a public event to endear the monarchy to the nation. The First World War had then just ended.
That marriage set the style for every royal wedding to follow.
Princess Elizabeth's wedding to Prince Phillip on November 20, 1947 was the first royal wedding in which BBC cameras were allowed inside Westminster Abbey.
This time too Britain was emerging from the Second World War, and the national mood lifting.
The country was broke and cities scarred by bombs and it was decided that a national celebration was just what the country needed.
Then, for the first time, a royal wedding was telecast live when Princess Margaret married photographer Anthony Armstrong Jones on May 6, 1960.
It was seen by an audience of 300 million across the world.
Since then, royal weddings became huge spectacles that drew billions of people across the world.
They were events that were intricately planned and choreographed to the very second, particularly the weddings of Queen Elizabeth's children.
On November 14, 1973, Princess Anne married Captain Mark Philips.
That year, Britain was facing economic meltdown with power cuts, shortages and large deficits.
This wedding in Westminster Abbey was estimated to have been watched live by 500 million viewers across the globe.
But the royal wedding of the 20th century was undoubtedly that of Prince Charles and Lady Diana on July 29, 1981, which was considered more splendid and magnificent that any other royal wedding in history.
But it was also held in the backdrop of another difficult period in Britain's contemporary history. There was unrest and riots in some cities amidst a crippling recession.
It was also the first time that a royal couple kissed on the balcony of the Buckingham palace during the customary post-wedding appearance before thousands of people.
This wedding was estimated to have been watched by 750 million people across the world.
On July 23, 1986, Prince Edward married Sarah Fergusson.
The couple followed the new tradition set by Prince Charles and Lady Diana and kissed on the balcony to the delight of thousands of people gathered around Buckingham Palace.