The Queen's grand-daughter Princess Eugenie marries Jack Brooksbank tonight at 9pm Australian time. It will be the second big royal wedding this year and at the same venue, St George's Chapel at Windsor Castle.
While it may be at the same place as Prince Harry and Duchess Meghan's wedding in May, the ceremony, reception, guest list and other individual flourishes are expected to be quite different. For a start, the wedding is "plastic free".
Here is what else we know about tonight's big event and its stars, broken down into some handy headings.
The bride was born Princess Eugenie Victoria Helena of York on March 23, 1990, and is currently ninth in line to the throne.
Her parents are Prince Andrew, the Duke of York and Sarah, Duchess of York, formerly Sarah Ferguson. The 27-year-old is the younger sister of Princess Beatrice of York.
She studied English and history of art at university, and works for the contemporary art gallery Hauser and Wirth in London.
She is not on a "salary" as such from the Queen but she is said to be worth about $6 million, and the rent of her apartment at St James Palace is covered by her dad.
Her fiancé Jack Brooksbank is 31 years old and has been described as a socialite and an excellent skier.
He is the UK brand ambassador of Casamigos Tequila, which was co-founded by actor George Clooney.
Like the guest list, the bridal party is a glamorous mix of royals, socialites and celebrity children.
Front and centre will be the two oldest children of Prince William and Duchess Catherine, Prince George and Princess Charlotte.
Princess Eugenie's sister Princess Beatrice, 30, will be her maid of honour, while Mr Brooksbank's brother Thomas will be his best man.
The service will begin at 11am London time (9pm Eastern Daylight Saving Time) and is expected to last an hour. The couple will then take part in a short procession ride through the streets of Windsor.
The Dean of Windsor, David Conner, will marry the couple while the Archbishop of York, John Sentamu, will lead the prayers.
More than 800 guests are expected to witness the event in the 15th century St George's Chapel.
READ NEXT: Princess Eugenie's and Jack Brooksbank's Order of Service revealed
Just as the Duke and Duchess of Sussex did, Eugenie and Jack have invited 1200 members of the public into the grounds of Windsor Castle for their wedding. These people took part in a ballot which apparently had more than 100,000 entries.
Among the guests will be most senior members of the Royal Family – but not Camilla, Duchess of Cornwall and wife of Prince Charles as she has a prior engagement. It is also unclear if Eugenie's 97-year-old grandfather, the Duke of Edinburgh, will also attend.
The event is also expected to be quite star-studded as the princess is close friends with model Cara Delevingne and singer Ellie Goulding. Singer Robbie Williams is certain to be there as his daughter Theodora Rose has been named as one of the flower girls.
And as the groom is a brand ambassador for Casamigos Tequila, a company owned by George Clooney, it is believed that the actor and his wife Amal will also attend. The Clooneys also attended the wedding of the Duke and Duchess of Sussex.
In line with a 95-year-old tradition, Eugenie's wedding ring will be made from extremely rare Welsh gold.
This tradition dates back to the wedding of George VI to Elizabeth Bowes Lyon (the Queen mother, the bride's great-grandmother) in 1923 when the royal family was given a nugget of gold from the now-closed Clogau St David's mine in North Wales.
It has been revealed in the Order of Service that Jack will not wear a wedding ring, unlike his soon-to-be cousin by marriage, Prince Harry who chose to wear a wedding ring when he married Duchess Meghan in May.
No boozy fruit cake for this party pair. The centrepiece of the luncheon reception will be a five-tier red velvet and chocolate cake.
It is being made by London-based cake designer Sophie Cabot, who described it as "special and unique", featuring rich autumnal colours and detailed sugar work – and apparently 400 eggs and almost 20kg of sugar!
Like the wedding of the Duke and Duchess of Sussex, there will be two reception events.
The Queen is expected to host a champagne reception at Windsor Castle during the afternoon and in the evening, around 400 guests will celebrate with the newlyweds at an event hosted by the princess' parents at an event reportedly at Royal Lodge in Windsor, the official country residence of the Duke of York.
The festivities kick on the day after the wedding (tomorrow) and it's rumoured to have a country fair theme with fairground rides, food stalls and even dodgem cars.
The groom will not be getting a title and will remain a "member of the public".
The bride will be known as Her Royal Highness (HRH) Princess Eugenie, Mrs Jack Brooksbank once married
WATCH THIS: Princess Eugene's parents the Duke and Duchess of York before they got married (and then divorced)
The couple are already living together – in Ivy Cottage, a three-bedroom home at Kensington Palace.
Before Eugenie moved in with Jack four months ago, she was living with her sister Princess Beatrice in a four-bedroom apartment in St James' Palace.