They were joining the Queen and more than 30 members of the royal family, gathered to witness the ceremony, alongside the bride and groom’s trusted inner circle of friends.
Harry’s much loved former nannies Tiggy Legge Bourke, now Tiggy Pettifer, and Jessie Webb were also invited to see their young charge’s milestone day.
Williams, who was joined by her husband Reddit co-founder Alexis Ohanian, is a close friend of Meghan.
Winfrey reportedly welcomed Meghan’s mother Doria Ragland to her Florida home a few weeks ago, and the bride is said to be friends with Amal Clooney.
Former prime minister Sir John Major, who was appointed a special guardian on legal matters to Princes William and Harry following the death of their mother Diana, Princess of Wales, was present with his wife Dame Norma.
Diana’s former flatmate Carolyn Bartholomew, who was a school friend of the princess and shared a London flat with shy Lady Diana Spencer before she wed the Prince of Wales, was also there, as was Julia Samuel, one of Diana’s best friends and now godmother to Prince George.
The princess’s three siblings, Earl Spencer, Lady Sarah McCorquodale and Lady Jane Fellowes, were among the 600-strong congregation.
Sarah, Duchess of York, the Duke of York’s ex-wife, who is said to have a frosty relationship with her former father in law the Duke of Edinburgh, was seated near the entrance to the Quire, next to the choir, away from her former in-laws.
She was on the left hand side of the chapel, rather than on the right where the royals were placed.
Meghan’s best friends and confidantes, Canadian stylist Jessica Mulroney, Benita Litt, American actress Janina Gavankar and author Lindsay Roth, were gathered in the 15th century church.
The friends have been supporting Meghan in the difficult days ahead of the wedding after her father Thomas Markle pulled out of attending.
Ms Litt, whose two daughters are bridemaids, was seated next to Meghan’s mother Doria Ragland.
Misha Nonoo, the fashion designer credited with introducing Harry to his future wife, also had a VIP seat in the venue as did Meghan’s best male friend Markus Anderson who is director of members club Soho House where the couple’s blind date took place in the summer of 2016.
Members of the royal family alongside the Queen and the Duke of Edinburgh included the Prince of Wales, the Duchess of Cornwall, the Duke and Duchess of Cambridge, the Duke of York and Princess Beatrice, the Earl and Countess of Wessex and their children Lady Louise Mountbatten-Windsor and Viscount Severn, the Princess Royal, Zara and Mike Tindall and Peter and Autumn Phillips.
Princess Eugenie and her fiance Jack Brooksbank were no doubt thinking of their own nuptials due to take place in the same chapel in the autumn as they witnessed the proceedings.
Harry’s childhood friend Thomas van Straubenzee and family were in the Quire, along with Emilie van Cutsem, the widow of Charles’s close friend Hugh van Cutsem.
Other friends included Arthur Landon and the Queen’s racing manager John Warren also joined the selective guests in the wooden stalled Quire.
Guests seated in the Nave included David and Victoria Beckham, actor Idris Elba and singer James Blunt, Harry’s ex-girlfriend Chelsy Davy, the Duchess of Cambridge’s family the Middletons, including her sister Pippa and former rugby star Jonny Wilkinson.