What will Kate Middleton wear? How will Beckhams make their entrance? What will Beatrice wear on her head? The guests' arrival at Prince Harry and Meghan Markle's wedding is the (second) best bit of the day.
From Pippa Middleon's £495 dress to the arrival of Meghan's LA contingent and Amal Clooney's incredible Stella McCartney creation, there are so many moments we are obsessed with.
The ceremony itself - which will be conducted by Reverend Michael Bruce Curry, the Presiding Bishop of the Episcopal Church and the Reverend David Conner, the Dean of Windsor, with the vows read by Justin Welby, the Archbishop of Canterbury - will start at 12pm, and will last for around an hour. Immediately afterwards, the happy couple will embark on a carriage ride around Windsor, which will take 25 minutes.
But before that, check out all the guests as they arrive...
All The Guests At Meghan & Harry's Wedding
1 of 31Earl Spencer and Lady Karen Spencer
Prince Harry's uncle - and Princess Diana's younger brother, with his wife, Lady Karen Spencer.
2 of 31James Blunt and Sofia Wellesley
The "Beautiful" singer and his wife Sofia arrive at the royal wedding
3 of 31Idris Elba and Sabrina Dhowre
Luther star Idris Elba and his then-fiancee Sabrina Dhowre were surprise guests at the wedding
4 of 31Oprah Winfrey
Oprah arrived at the wedding dressed in Stella McCartney
5 of 31Carole Middleton
Pippa and Kate Middleton's mother arrived at the royal wedding in an ice-blue skirt suit and matching fascinator
6 of 31Amal and George Clooney
Amal and George Clooney both looked incredible - Amal is 100% topping the best-dressed list in her mustard yellow Stella McCartney ensemble
7 of 31Cressida Bonas
Harry's ex Cressida was spotted in London-based brand Eponine
8 of 31Victoria and David Beckham
Victoria and David Beckham made their entrance at the royal wedding - she's wearing a navy dress that's not a million miles away from the dress she wore to Kate and WIlliam's wedding in 2011.
9 of 31Pippa Middleton and James Matthews
Pippa Middleton was spotted wearing a £495 dress by brand The Fold - just one day before her own wedding anniversary
10 of 31Chloe Madeley and James Haskell
Chloe Madeley arrived with her fiancee - England international rugby player James Haskell
11 of 31Kitty Spencer
Lady Kitty Spencer, Prince Harry's cousin, arrived wearing a forest green floral dress by Dolce and Gabbana
12 of 31Fergie, Duchess of York
Sarah Ferguson, Duchess of York, Prince Andrew's ex wife and the mother of princesses Beatrice and Eugenie arrives at St George's chapel
13 of 31Julia Carey and James Cordon
The actor and talk show host arrived with his wife, Julia
14 of 31Joss Stone
The musician, a close friend of Prince Harry, arrived at St George's chapel with a friend.
15 of 31Carey Mulligan and Marcus Mumford
The Great Gatsby actress arrives wearing William &Son with her husband, musician Marcus Mumford.
16 of 31Serena Williams and Alexis Ohanian
Tennis star - and friend of Meghan's - arrived wearing Versace with her husband Alexis Ohanian
17 of 31Princess Anne
Prince Harry's aunt arrives at the chapel in a red and black ensemble
18 of 31Princess Beatrice
Prince Harry's first cousin wore a dark blue dress by Gainsbourg paired with a matching Fiona Graham headband. She wore shoes by Valentino.
19 of 31Zara Tindall and Mike Tindall
The Olympic equestrian (nee Phillips) and one of Prince Harry's first cousins, arrived with her husband.
20 of 31Princess Eugenie
Princess Eugenie, one of Prince Harry's first cousins, arrived in a powder-blue Jackie-Kennedy-inspired outfit. The dress is by Roksanda Viola and the pill-box hat is by Stephen Jones.
21 of 31Sophie, Countess of Wessex
The countess (married to Prince Harry's uncle Edward) arrived wearing a bespoke bodice top and midi skirt by British couture and ready-to-wear designer Suzannah.
22 of 31Queen Elizabeth II
Her Majesty the Queen arrives shortly before the bride wearing a flared silk dress in lime, lemon, purple and grey. Her coat is lime silk tweed. Both are by Stuart Parvin. The Queen's hat is also lime silk tweed by Angela Kelly and is adorned with handmade crystals and pearls by Lucy Price.
23 of 31Camilla, Duchess of Cornwall
The duchess of Cornwall arrives with Prince Charles. She is wearing a pink silk coat dress by Anna Valentine and her hat is by royal favorite Phillip Treacy.
24 of 31Catherine, Duchess of Cambridge
Prince Harry's sister-in-law sits in the chapel between Prince Andrew and the Duchess of Cornwall. She wears a yellow silk coat by Alexander McQueen -- who also famously designed her wedding gown when he married Prince William in 2011 -- paired with a Phillip Treacy hat and Jimmy Choos.
25 of 31Doria Ragland
Mother-of-the-bride Doria Ragland, who rode partway to Windsor with Meghan, arrives at St George's Chapel in a mint green ensemble by Oscar De la Renta. Her hat is by Stephen Jones.
26 of 31Chelsy Davy
Prince Harry's former girlfriend arrives dressed in navy.
27 of 31Gina Torres
The American actress was one of Meghan's Suits co-stars, many of whome who were invited to the ceremony.
28 of 31Princess Charlotte
Prince Harry's niece was one of the flower girls. She looked adorable in her Givenchy dress and flower crown.
29 of 31Sarah Rafferty
Actress Sarah Rafferty - who co-starred with Meghan in Suits -arrives in a navy blue ensemble
30 of 31Patrick J Adams
The actor who played Meghan's on-screen love interest in Suits looked dapper as he arrives for the ceremony with his wife Troian Bellisario, who wore a cream bell-sleeved dress with embellished shoulders.
31 of 31Abigail Spencer and Priyanka Chopra
The actors - both friends of Meghan - looked happy and relaxed as they arrived at the chapel together.