The Duke and Duchess of Sussex will be absent from the Thanksgiving reception, held at the Guildhall.
Guests at the reception include many of those who attended the religious service, including royals and senior politicians.
The Duke and Duchess of Sussex arrived to boos at St Paul’s Cathedral this morning, ahead of the Service of Thanksgiving.
The couple arrived after the Earl and Countess of Wessex, and their two children, and Princesses Beatrice and Eugenie along with their husband's.
Harry and Meghan were spotted holding hands and smiling broadly as they walked up the steps of the cathedral, while cheers could be heard from the crowd.
The Duke and Duchess of Sussex were seated in the second row of the congregation for the Service of Thanksgiving, alongside Princesses Beatrice and Eugenie and their husbands, and Lady Sarah Chatto, the daughter of Princess Margaret, and her family.
Prince Harry and Meghan Markle arrive at St Paul's TOBY MELVILLE
Harry and Meghan are seated behind the Earl and Countess of Wessex who are in the front row with their children, Lady Louise Mountbatten-Windsor and Viscount Severn, and the Duke and Duchess of Gloucester.
Across the aisle, the Prince of Wales and Duchess of Cornwall, are seated on ornate chairs, alongside the Duke and Duchess of Cambridge and the Princess Royal and her husband, Vice Admiral Tim Laurence.
Harry and Meghan were forced to squeeze past his cousins Princess Beatrice and her husband Edoardo Mapelli Mozzi, and Princess Eugenie and her husband Jack Brooksbank, who were already seated, to get to their places.
Britain's Prince Harry and Meghan, Duchess of Sussex, are greeted as they arrive POOL
Harry and Meghan hold hands and enter the Cathedral HENRY NICHOLLS
Harry was spotted, with his mouth open, appearing to be enjoying a joke with another royal seated across the aisle.
Beatrice, sitting a few seats down, was also grinning in the same direction.
The royal family has come together with the Duke and Duchess of Sussex in honour of the missing Queen at a special Jubilee service of thanksgiving.
Harry and Meghan joined the Prince of Wales, the Duchess of Cornwall and the Duke and Duchess of Cambridge as nearly 40 royals gathered for the celebration in St Paul’s Cathedral in London.
The Duke and Duchess of Sussex walk down to aisle of St Paul's to find their seats POOL
Meghan, 40, was pictured in a stylish cream coat dress, with matching hat and shoes, while the Duchess of Cambridge sported a lemon dress by Emilia Wickstead and fascinator by designer Philip Treacy.
The Duke and Duchess of Sussex were greeted on the steps of St Paul's by the Lord Mayor of London.
The couple were not prohibited from appearing on the Buckingham Palace balcony yesterday and instead watched proceedings from Horse Guards Parade.
They were captured through an open window as they caught up with other members of the family, including Peter Phillips' daughters Savannah, 11, and Isla, 10, and Zara and Mike Tindall's daughter Mia, eight.
The Queen pulled out of the Thanksgiving Service, after experiencing "discomfort" at the parade at Buckingham Palace.
The decision was made with "great reluctance" after pondering on the "journey and activity required", the Palace reported.