Royal wedding 2018: What we know so far

The chapel has a capacity of around 800.

London florist Philippa Craddock has been tasked with decorating the chapel. Her team plans to use white garden roses, peonies and foxgloves, as well as branches of beech, birch and hornbeam for the floral displays, which will be distributed to local charities after the wedding.

Many of the plants will be sourced from the gardens and parkland of the royally owned Crown Estate and Windsor Great Park, according to Kensington Palace.

The couple will exchange vows at noon (7 a.m. EDT) in a ceremony expected to last an hour.

The first guests to arrive for the celebrations will be the 1,200 ordinary members of the public who will share in the festivities from the grounds of Windsor Castle. They are expected to arrive from 9 a.m. (4 a.m. ET).

The main wedding guests are due between 9.30 a.m. and 11 a.m. (4.30 a.m. to 6 a.m. ET) and will be driven to the Round Tower by coach before walking to the South Door of St. George's Chapel.

Lastly, the royal family will head for the chapel via the Galilee Porch at 11.20 a.m. (6.20 a.m. ET). Some are expected to arrive by foot, while others will travel by car.

Kensington Palace say that Harry and William will go to the chapel together on foot and will enter the West Steps, where they will greet 200 charity representatives.

Meghan's mother, Doria Ragland, will spend the night before the wedding with her at a hotel and accompany her to Windsor on the day. Her father, Thomas Markle Sr., will not be attending, amid concerns over his health and a controversy over staged photos. Prince Charles, Harry's father, will walk Meghan down the latter part of the chapel aisle in his place.

While the congregation is gathering, Meghan and her mother will depart their hotel and travel to the castle via the Long Walk, where members of the public will be able to get their first glimpse of the bride. The car will stop at the castle to let Meghan's mother out and pick up some of the bridal party before continuing to the church. There will be six young bridesmaids and four page boys in total, with Prince Harry's nephew Prince George and niece Princess Charlotte among them.

Meghan has opted not to have a maid of honor, according to Kensington Palace. "She has a very close-knit group of friends and did not want to choose one over the other," said Jason Knauf, Prince Harry's communications secretary.

In an unprecedented step for a royal bride in the UK, Meghan will walk unescorted down the first section of the chapel aisle, CNN has learned. She will be joined by Prince Charles at the Quire, where the main royal guests will be seated.

After the ceremony has ended at 1 p.m. (8 a.m. ET), the newlyweds will greet the 200 representatives of Prince Harry's charities outside the chapel.

They will then leave Windsor Castle in a carriage for a roughly two-mile procession, traveling along the High Street through the town of Windsor, before returning to the castle by the Long Walk, according to the Palace. The procession is expected to take around 25 minutes.

They will travel in an Ascot Landau carriage pulled by Windsor Grey horses. The royal family owns five Ascot Landaus and uses them regularly for official events. Prince Harry traveled in one during the carriage procession at the wedding of the Duke and Duchess of Cambridge in 2011.

Windsor Grey horses also have a long royal pedigree -- they have been pulling the carriages of British monarchs and members of the royal family since the 1900s.

After the procession, the couple and guests will then attend a reception hosted by Queen Elizabeth II at St. George's Hall in the castle grounds, bringing the public aspects of the day to a close.

The final moment the public will get to share in will be when the bride and groom leave the castle grounds for a smaller evening reception for around 200 friends and family hosted by Prince Charles, Harry's father, at Frogmore House, a country house south of Windsor Castle.

The Dean of Windsor, the Rt. Rev. David Conner, and the Archbishop of Canterbury, Justin Welby, the leader of the Church of England, will officiate the ceremony. Markle is now a fully fledged member of the Church of England after she was reportedly baptized and confirmed by Welby in a secret ceremony in March. The couple have also invited an American bishop, the Most Rev. Michael Curry, head of the Episcopal Church and its first African-American leader, to give the address at their wedding.

Meghan will spend her final night as a single woman at the luxurious Cliveden House Hotel in Berkshire. On the morning of May 19, a car will take the bride and her mother to Windsor Castle.

As expected, Harry's older brother Prince William will step into the role of best man. Harry has also expressed his desire for his mother's side of the family to be involved in the service. The three siblings of the late Diana, Princess of Wales, who died two decades ago in a car accident, have been invited. One sister, Lady Jane Fellowes, will give a reading.

The palace will publish a full Order of Service on its website on the morning of the wedding so members of the public can follow the ceremony at home.

The couple have taken a very hands-on approach in planning their big day, right down to their selection of music for the service, which will include several popular hymns and choral works. The chapel's director of music, James Vivian, will conduct the Choir of St. George's Chapel -- which was founded in 1348 and includes music from all ages in its repertoire.

State Trumpeters and an orchestra encompassing musicians from the BBC National Orchestra of Wales, the English Chamber Orchestra and the Philharmonia Orchestra will also provide music at the service.

The royal pair have also chosen to inject several more modern musicians and soloists into their ceremony. Karen Gibson and the Kingdom Choir -- considered one of the top ensembles in the country -- have been tapped to perform as has 19-year-old cellist Sheku Kanneh-Mason, who was the first black musician to win the BBC Young Musician of the Year award in 2016.

"I was bowled over when Ms. Markle called me to ask if I would play during the ceremony, and of course I immediately said yes," Kanneh-Mason said on Twitter. "What a privilege to be able to play the cello at such a wonderful event. I can't wait!"

More than 250 members of the British Armed Forces will also be involved on the day, an acknowledgment of Harry's time in the army. Personnel from a number of units including the Royal Marines and the Windsor Castle Guard will line the local streets, with music provided by the Band of the Irish Guards.

Details about who will be attending the ceremony (and the two receptions) are still very sparse; in fact, we know more about who won't be there. Kensington Palace has announced that the royal couple are not inviting political leaders, at least not on the basis of their official positions.

Some political figures may be present if they are personal friends of Harry and Meghan -- but that won't include Barack and Michelle Obama, according to a royal source. The source would not say however whether the Obamas had been invited.

The White House and Downing Street confirmed that neither US President Donald Trump nor UK Prime Minister Theresa May had received invitations.

The invitations were made by Barnard & Westwood, a London printer and bookbinder that has been making invitations for the royal family since the 1980s, according to Kensington Palace.

Aside from the 600 (or so) guests lucky enough to be inside the chapel, more than 2,640 people are being invited inside the grounds of Windsor Castle on the big day.

The invitees -- including 100 local schoolchildren and 610 Windsor Castle community members -- will be able to watch the arrivals of the bride and groom and their guests and to watch the newlyweds depart the castle on their carriage procession.

Visitors to Windsor on the big day are being encouraged to gather on the Long Walk -- the final stretch of the procession route -- where big screens and food stalls will be available.

Crowds will also gather along the rest of the procession route through the town, which will be decorated with bunting and ceremonial banners, according to a statement from the borough of Windsor and Maidenhead. Local groups will provide live entertainment throughout the town center.

Rail operators will put on extra train services to and from Windsor, and for those traveling by road, 6,000 car parking spaces will be available close to the Long Walk, according to the borough.

Thames Valley Police, the force that operates in the borough of Windsor and Maidenhead, has overall command of the policing for the wedding and is supported by partner agencies including the Metropolitan Police and the British Transport Police, according to a spokesman for Thames Valley Police. The operation is one of the largest ever undertaken by the force.

According to a police statement, security in the area has already been stepped up, with armed and unarmed officers as well as search dogs and mounted police patrolling the streets of Windsor in the weeks leading up to May 19.

Police have warned that people traveling to the area by car on the day may be stopped by police, while British Transport Police will be patrolling train stations and carriages. Anyone arriving in Windsor by train will be screened and searched.

There are no details yet on the cost of security for the wedding or the number of officers involved.

Renowned fashion and portrait photographer Alexi Lubomirski will take the official photographs of the newlyweds at Windsor Castle after the ceremony.

The two are already familiar with Lubomirski, who photographed Harry and Meghan at Frogmore House in the weeks after they announced their engagement.

We're unlikely to know anything about Markle's wedding dress until the bride steps out on May 19. But that hasn't stopped the rumor mill.

Designers tipped to be among the likely candidates include the Canadian-born Erdem Moralioglu, French designer Roland Mouret and the Ralph & Russo duo, who designed the gown Markle wore in her engagement photographs.

The couple have asked for anyone wishing to send them a wedding gift to consider donating to one of several selected charities instead.

The seven organizations chosen by Prince Harry and Markle all work on issues the couple are passionate about, including women's empowerment, HIV, homelessness and the environment, according to a palace statement.

Guests will enjoy a non-traditional wedding cake made by pastry chef Claire Ptak. The lemon elderflower cake will feature buttercream and fresh flowers as decoration.

Ptak, who was raised in California and now owns London-based bakery Violet Cakes, was previously acquainted with Markle, who had featured the chef on her former lifestyle blog.

Kensington Palace says Ptak and the chefs who have been working in the Palace kitchens to make the final preparations will provide an update closer to the big day.

Despite rumors that the Spice Girls, Elton John, Ed Sheeran or Sam Smith could be performing at the second, evening reception, nothing has yet been confirmed by Kensington Palace.

While the wedding itself will be a public affair, the choice of honeymoon destination is a closely guarded secret.

Meghan and Harry will not depart for their honeymoon immediately after the wedding. Instead, they will undertake a public engagement in the week after the ceremony, according to Kensington Palace.

There's already a long list of locations being suggested as possible destinations, including Botswana (where the pair vacationed early in their relationship) and the Seychelles (where William and Catherine spent their first days as a newly married couple).