A personal touch had been added to the coffin - a wreath of flowers featuring foliage from the gardens of Buckingham Palace, Clarence House and Highgrove - with a handwritten card that appeared to have been penned by the King.
But viewers on social media noted the appearance of the insect inching its way across the card placed with the flowers on top of the coffin, alongside the crown.
“Did anyone else spot the spider catching a ride on Queen Elizabeth II coffin?” one Twitter user asked.
“The most famous spider in the world right now,” another user wrote.
The Queen’s funeral was held at Westminster Abbey, London and attended by 2,000 mourners, including world leaders such as US president Joe Biden and 200 key workers and members of the public
Thousands more have lined the streets of the city ahead of the state funeral, which is the first held in Britain for 57 years.
During the service the Countess of Wessex was spotted dabbing a tear from her eye and Princess Beatrice looked overcome with emotion at one point.
Prince George and Princess Charlotte joined their parents walking behind the coffin when it entered the Abbey and were given their copies of the order of service, turning the pages as they followed the proceedings.
The royal family were sat opposite foreign kings and queens including King Willem-Alexander of the Netherlands, Prince Albert of Monaco and King Felipe VI and Queen Letizia of Spain.
After the service at Westminster Abbey, crowds will see the coffin being taken to Wellington Arch as part of a ceremonial procession that will feature hundreds of military personnel and the royal family.
The coffin will continue its last journey from London to Windsor, where Her Majesty will be laid to rest.
Queen Elizabeth II passed away on Thursday 8 September at Balmoral Castle, Scotland aged 96.