It's the society wedding of the year—with reportedly a very specific dress code of different outfits for day and night to prove it. Pippa and her groom James Matthews' guest list will combine Middletons, royals, old friends, the cream of society, and a sprinkling of celebrity stardust. Here's what we know so far:
Carole and Michael
Dad Michael will be walking his second daughter down the aisle, while mum Carole has been closely involved with the planning. The reception will be held in the grounds of their home in Berkshire.
Pippa is exceptionally close to younger brother James, and the two have accompanied each other on grueling physical challenges for charity over the years, as well as being each other's date for social events. James could well be fulfilling usher duties on the big day.
Uncles Richard, Simon, and Nicholas
The Middleton side of the family has always stayed out of the spotlight, but dad Michael has three brothers. They and their families were all invited to William and Kate's wedding, so they're sure to be filli the pews at Pippa's too.
Adam and Rebecca
Kate, Pippa, and James are so close to their cousin Adam that he is one of Princess Charlotte's godfathers, and the three siblings attended his wedding in 2014.
Gary and Julie-Ann
Pippa's uncle Gary is her mom Carole's brother. A lthough he has ruffled feathers for speaking publicly about his nieces, family is family and he will be sure to attend with his fourth wife, Julie-Ann.
Gary's 14-year-old daughter from his second marriage has always been close to her cousins Kate and Pippa, so we may even see her acting as bridesmaid on the day.
The Duke and Duchess of Camrbidge
Kate, a key figure in the wedding, has been helping her sister plan the day, and is likely to take on the role of matron of honor in all but name. William will likely be there to just enjoy the day as a proud father to two tiny attendants.
Prince George and Princes Charlotte
The little prince is just two months away from his fourth birthday, and will be following in the footsteps of his dad and uncle Harry by taking on the role of page boy. Meanwhile two year old Princess Charlotte will be the sweetest little bridesmaid in all the land.
Pippa has known Harry for over ten years, and the two have always gotten along. Not only did Harry walk Pippa back up the aisle after the royal wedding, but they share many of the same friends.
THE MATTHEWS FAMILY
The groom's brother started his TV career in a reality show called Made In Chelsea, before moving on to the British version of The Bachelor. He has been dating model/reality star Vogue Williams for a few months, though probably not long enough for her to get a wedding invite.
David and Jane
Groom James has always been very close to his parents, and William and Kate even took time to meet them for a family dinner ahead of the big day. The couple own the luxury hotel Eden Roc in St. Barths.
Pippa Middleton with George Percy
Pippa's old university flatmate will inherit a dukedom some day, along with Hogwarts—better known as Alnwick Castle. George and Pippa were rumored to have dated, and they have holidayed together in the past, as well as accompanying each other to weddings and other high-profile social events.
Lady Catherine Percy
Pippa is also close to George's two sisters, and attended both of their weddings. She will be sure to invite Lady 'Katie' to her own, but the second sister is Lady Melissa Percy, who is currently getting divorced from Prince William's best friend Thomas Van Straubenzee. It's likely that Thomas will be at the wedding, but are relations cordial enough between the pair that Lady Melissa will be there too?
Pippa has attended the weddings of all three Marsham siblings—David, Michael, and Laura—whose father is the Earl of Romney. Laura married Prince William's other best friend James Meade, so there's plenty of overlapping friendship groups here.
Sam and Annabel Waley-Cohen
Sam and Annabel Waley-Cohen
The Middleton sisters have long been friends with the Waley-Cohens; Kate and Pippa were at school with Sam's brother Tom, and were devastated when he died of cancer at the age of 20. Kate and Pippa stayed in close contact with the family, and raised money for the charity that was set up in his name (most notably at a roller disco where Kate was famously pictured taking a spill.) Both sisters attended Sam and Annabel's wedding in 2011.
Alice and Gerald Avenel
Teacher Alice is one of Pippa's oldest friends. They were at school and university together—both playing on the hockey and tennis teams—and have also accompanied each other on vacation. Pippa, Kate, and William were all at Alice and Gerald's wedding in 2012.
Camilla and Sam Holland
Pippa and Camilla met on a cooking course they attended when they had both just finished school, and have remained close friends. Pippa helped organize Camilla's wedding to Sam—the grandson of late movie director Lord Richard Attenborough—in 2012, and also gave a reading in the church.
Pippa and Camilla met at Edinburgh University. They are friends with each others' families and have been on holiday together. Camilla is one of Pippa's few remaining unmarried friends, although she's likely to attend with her long-term boyfriend Oliver Jenkinson.
Thierry and Patrick Heathcoat-Amory
Another of Pippa's closest girlfriends from Edinburgh University is so tight with the Middleton clan that when she married in 2012, Michael gave her away, since her own father died when she was a child.
Charlie and Anneke Gilkes
Pippa briefly dated Charlie when they were at university together, but they stayed friends and years later she attended his wedding, along with Prince Harry. At the Diamond Jubilee River Pageant, the Middletons shared a boat with Charlie and Anneke.
Thomas Van Straubenzee
William's best friend since childhood is in a very tight-knit group with Kate, Pippa and Harry. He accompanied William on his gap year, was one of his ushers and is godfather to Princess Charlotte.
Despite previous reports that Pippa has a "no ring, no bring" policy for her wedding, meaning that guests could only bring their partners if they are either married or engaged, The Daily Telegraph now reports that Markle will be joining in the full celebrations
James Middleton has been dating former actress and TV presenter Donna Air for around four years, but as they are not engaged, Donna might only come to the evening part of the celebrations.
The Bahrain-born, New York-based designer is married to Charlie Gilkes' older brother Alexander, but they separated last year so chances are not both of them will attend.
This story originally appeared on Townandcountrymag.com.
* Minor edits have been made by the Townandcountry.ph editors.