Windsor, England CNN  — 

Prince Harry and his brother, Prince William, pleased throngs of royal fans in Britain as the pair went on the traditional “walkabout” Friday evening, the eve of Harry’s wedding to American Meghan Markle.

The two brothers made their way down Castle Hill in Windsor, on the western outskirts of London where the wedding will take place, and spent 10 minutes with the crowd, longer than many fans there had expected.

Prince Harry greets members of the public on Friday evening.

Prince Harry appeared relaxed, in a light gray blazer and shirt unbuttoned at the collar. At one point he stopped for a long chat with a young child, and he accepted a soft toy from a well-wisher.

Prince Harry and Meghan Markle will get married Saturday at St. George’s Chapel in Windsor, in a ceremony that will be watched by millions around the world.

The couple are spending the night apart, each staying in a luxury hotel close to the castle where they will take their vows.

After a turbulent week that culminated in confirmation that her father, Thomas Markle Sr., would not be able to attend the wedding, Markle will be staying at Cliveden House Hotel with her mother, Doria Ragland.

The pair will travel together by car to Windsor on Saturday morning, their route to the chapel taking them along the picturesque Long Walk past crowds of well-wishers.

When the US actress next passes along the leafy avenue, it will be as a royal bride in a horse-drawn carriage, with her husband Prince Harry beside her.

The groom-to-be, meanwhile, will spend Friday night at Coworth Park Hotel in Ascot with Prince William, who is acting as his best man.

The couple’s 600 or so wedding guests will also be preparing for the big day. Among them will be the Queen, Prince Philip and a bridal party made up of six young bridesmaids and four page boys – Prince George, 4, and Princess Charlotte, 3, among them.

Meghan has chosen not be chaperoned as she walks down the aisle of the chapel nave, a move that is unprecedented for a royal bride in Britain and can be seen as a bold feminist statement.

Palace officials confirmed Friday that Prince Charles, Harry’s father, would accompany her for the final part of the procession, down the aisle of the Quire to the altar, in place of Thomas Markle, ending speculation that her mother might step in.

The ceremony will have a distinctly modern feel. The couple has chosen a modern set of wedding vows, and the text of the formal parts of the service are taken from Common Worship, the Church of England’s standard liturgy, first published in 2000. It is thought to be the first time that this text has been used in a royal wedding.

The introit music, Handel’s “Eternal Source of Light Divine,” will be sung by soprano Elin Manahan Thomas, and The Kingdom Choir, a group of 20 gospel singers, will perform the Ben E. King classic “Stand By Me.” The ceremony will end with the orchestra playing “This Little Light of Mine,” a gospel song that became synonymous with the civil rights movement in the United States.

Watching crowds

The couple have invited 1,200 ordinary members of the British public to watch from inside the castle grounds as their 600 guests arrive. The guest list has been kept under wraps, so commentators will be looking out for familiar faces – including cast members of “Suits,” the legal drama in which Markle made her name – as they make their way to the chapel’s South Door.

The royal guests will then come in through a door leading to the chapel’s Galilee Porch before Meghan makes her grand entry via the West Gate steps, beneath a spectacular stained glass window.

The Dean of Windsor, the Right Reverend David Conner, will conduct the service, while the Archbishop of Canterbury, Justin Welby, will officiate. In a break with custom for a UK royal wedding, an American bishop, Michael Curry, will give the sermon. Curry is the presiding bishop of the Episcopal Church, the US branch of the Anglican Communion, of which the Archbishop of Canterbury is the spiritual leader.

Authorities expect many thousands of people to flock to the historic town of Windsor to see the pair, after the wedding ceremony, process through its narrow streets and back up the Long Walk to Windsor Castle. Some are already camping out by the barriers to ensure they get a good spot.

While the English weather is generally anything but reliable, it looks pretty much picture-perfect for Saturday, CNN forecasters say. A few early clouds will give way to a mostly clear sky with plenty of sun and temperatures climbing to a mild 20 degrees Celsius (68 degrees Fahrenheit) after a cool morning start.

More than 250 members of the Armed Forces will take on ceremonial duties on the day, lining the streets, providing an escort for the procession and flanking the entrance to St. George’s Chapel. A rehearsal in Windsor on Thursday gave a glimpse of the pageantry.

Harry, who’s sixth in line to the throne, has a personal connection with the regiments and units taking part, having served in the British armed forces, completing two tours of duty in Afghanistan.

A carriage is driven through the streets of Windsor on Thursday during a rehearsal for the procession of Harry and Meghan's wedding.

Two receptions

After the procession, which will last about half an hour, Harry and Meghan will entertain their guests at two receptions – and the public portion of their day will be over.

All 600 wedding guests are invited to the first reception, hosted by the Queen at St. George’s Hall in the castle grounds. However, only 200 of their closest friends and family members will attend a smaller, evening reception hosted by Prince Charles at Frogmore House, south of Windsor Castle.

Police on motorcycles patrol around Windsor on Thursday.

Throughout the day, a major security operation will be in place to safeguard the couple, their guests and all the members of public who turn out to cheer them on, Thames Valley Police said.

Security measures include extra cameras monitoring vehicles and visitors in Windsor, additional vehicle barriers and mounted patrols on the streets. People are also banned from flying drones in the area.

There’s a huge media presence in the town, as broadcasters from around the world prepare to screen one of the most highly anticipated events of the year.

Union Jack flags are displayed in the street in front of Windsor Castle ahead of the royal wedding.

Father absent from wedding

After a week of tumult fueled by UK tabloid coverage, Markle confirmed Thursday that her Mexico-based father, who had been expected to walk her down the aisle, would not be present Saturday.

“Sadly, my father will not be attending our wedding. I have always cared for my father and hope he can be given the space he needs to focus on his health,” she said in a statement released by Kensington Palace.

Plans for her father to walk her down the aisle were thrown into question in the week before the ceremony amid a controversy involving staged photos captured by an American paparazzo and concerns over the elder Markle’s health.

Meghan Markle has been in contact in recent days with her father, who told her he was unable to attend the wedding on medical advice, CNN has learned.

CNN’s Max Foster contributed from Windsor and Angela Dewan contributed from London.