The royal guests, the posh potties, lavish party and more on Pippa Middleton’s wedding

This is a July 6, 2016 file photo of Pippa Middleton and James Matthews on day nine of the Wimbledon Championships at the All England Lawn Tennis and Croquet Club, Wimbledon London. Middleton and Matthews will marry on Saturday.
This is a July 6, 2016 file photo of Pippa Middleton and James Matthews on day nine of the Wimbledon Championships at the All England Lawn Tennis and Croquet Club, Wimbledon London. Middleton and Matthews will marry on Saturday. Associated Press

Six years ago when her older sister, Kate, married Britain’s Prince William and became a royal in a lavish wedding, Philippa “Pippa” Middleton stole the thunder.

She did it by wearing a figure-hugging, white bridesmaid’s gown by Alexander McQueen that quite nicely showcased her rear view. Social media sighed and crowned the commoner sibling with Twitter hashtags. Her bum became a star that day, earning a Facebook fan page and a shout-out from Justin Timberlake.

Now it’s 33-year-old Pippa’s turn to marry on Saturday and anyone who has ever had a sister has to wonder whether Kate wouldn’t like to exact just a little bit of sibling revenge. (Just a little.) Eyes will be watching.

Pippa’s wedding to multi-millionaire hedge fund manager James Matthews is one of the country’s hottest social events of the year. The wedding won’t be broadcast worldwide like her sister’s, but people have been following the preparations very closely.

Here’s what is known so far.

The Groom

He owns a palatial house in London’s Chelsea neighborhood and owns a private jet.

He’s rich. Need we say more?

All right, here it is. He’s 41, eight years older than Pippa. He’s a former professional race car driver who took after his wealthy father in the sport.

He has a flashy, proud-to-be-promiscuous younger brother named Spencer who starred in a British reality TV show, “Made in Chelsea,” about rich 20-somethings living in London.

James met Pippa more than a decade ago when the Middletons vacationed in the Caribbean island of St. Bart’s, where his family owns a resort, according to NBC’s Today show.

They dated for a few months in 2012 but started dating seriously in 2015.

When James proposed in July 2016 he gave her a stunning Art Deco-style ring featuring a 3.5-carat Asscher-cut diamond surrounded by a halo of smaller diamonds said to worth more than $250,000.

The Dress

This is one of the most-guarded secrets about the day. British couturier Giles Deacon is said to have won the honor of designing the country’s most anticipated gown of the season.

Paparazzi spotted him outside Pippa’s home last fall carrying a garment bag, and there has been buzz ever since.

Deacon’s celebrity clientele include Sarah Jessica Parker, Kerry Washington, Cate Blanchett and Kate Hudson, according to Hello! magazine.

He has not confirmed that he designed the gown. But there better not be a bustle on the back because we know what people will be looking for.

Pippa will reportedly wear custom shoes by Manolo Blahnik.

The Wedding Party

Pippa’s royal niece and nephew — Prince George, 3, and Princess Charlotte, 2 — will serve as pageboy and bridesmaid for their auntie’s big day, Kensington Palace has confirmed.

These two are the odds-on favorites to be the scene-stealers.

Kate reportedly told people at a Buckingham Palace garden party this week that she’s a bit worried about how the kids will behave.

“She said she was hopeful that they would be good but you never know at that age,” party guest Andrew Bates blabbed to reporters, according to ABC News.

Though American brides typically choose bridesmaids close to their own age, Brits don’t always — thus explaining Charlotte’s role as bridesmaid at age 2.

Though Pippa was her sister’s maid of honor, it’s not known if Kate will return the favor.

Royal watchers predict that Kate will sit this one out and find an important behind-the-scenes role so she doesn’t upstage the bride.

ET reports that James’ paparazzi-bait younger brother, Spencer, will be his best man. He’ll no doubt be camera ready.

The Guest List

Pippa can boast of five British royals at her wedding — her sister, George, Charlotte, Prince William and Prince Harry.

Yada yada yada … and Meghan Markle!

The American actress, who stars in the USA network’s legal drama, “Suits,” is dating Prince Harry.

Weeks ago there had been scuttlebutt that Pippa would not allow single “plus-ones” at her wedding to avoid getting upstaged by, oh, someone’s American girlfriend.

This will be one of the first public outings for Harry and his celebrity gal pal, who was seen arriving at Kensington Palace on Wednesday.

Many see the fact that she is there as a sign that their relationship has grown serious.

Not to get ahead of ourselves, but, ooh, another royal wedding?

The Theme

The bride and groom are both Brits so, of course, the theme of the day is — Scottish?

Pippa and James are fans of Scotland, according to The Daily Mail, which revealed the wedding theme.

Pippa went to school at Edinburgh University and James’ father, David, owns a castle and 10,000-acre estate near Loch Ness.

David Matthews’ real estate deal came with a courtesy title — Laird of Glen Affric — which will pass to James one day, making Pippa Lady Glen Affric.

Pippa’s 300 guests will dine on haggis canapés and lamb from the Glen Affric region of Scotland. Scotch whiskey will be served. A bagpiper will play and, according to the Daily Mail, James will incorporate tartan somehow in his wedding clothes, though it’s anyone’s guess if he’ll wear a kilt.

Another odd tidbit: An “anonymous Russian donor” has reportedly provided 17 pounds of beluga caviar for the festivities.

Don’t even get us started.

The Festivities

The couple will tie the knot at St. Mark’s Church, a 12th-century house of worship in Englefield, Berkshire, about six miles from Bucklebury, where Pippa grew up.

British media report that guests will enjoy a cocktail reception at the Englefield House, a private estate close to St. Mark’s Church, then travel to the Middleton private home in Bucklebury for the rest of the day.

Paparazzi posted photos this week of a huge glass marquee — aka a giant greenhouse — set up on the estate.

According to Vogue, the structure, about 140 feet long and 40 feet wide, was shipped in from Belgium and can fit up to 350 people.

And check out the posh porta potties that will be available. The posteriors — royal and otherwise — will be quite pampered at this affair.