Royal wedding: The schedule for Prince Harry and Meghan Markle's big day
Sky News is screening the proceedings with Kay Burley presenting from a special studio on the Long Walk.
Members of the public who have been invited to watch the wedding day from the grounds of Windsor Castle begin to arrive
Wedding guests begin arriving at the castle's famous Round Tower by coach. They will enter St George's Chapel through the South Door and take their seats
Members of the Royal Family begin arriving, entering via the Galilee Porch, some on foot and others by car
Harry and his best man Prince William are expected to appear at the Chapel's West Steps, probably on foot, walking past the thousands of spectators invited into the grounds of the castle. This will give Harry an opportunity to acknowledge the 200 representatives from charities he is associated with gathered in the Horseshoe Cloister at the bottom of the steps.
Following protocol, the Queen will be the last member of the Royal Family to arrive
With a minute to go, Meghan Markle is expected to turn up at the Chapel's West Steps by car, from her overnight accommodation, with some of her bridesmaids and pageboys. She will start her journey, which will take her past some of the crowds in the Long Walk, with her mother Doria Ragland - but when the car stops at the castle her mother will exchange places with her bridesmaids and pageboys, including Princess Charlotte and Prince George. Ms Ragland will enter the chapel by the Galilee Porch
The service starts. Everyone will already know most of what to expect as the order of service is being released at midnight on Friday
The newlyweds will emerge about an hour later at the West Steps of the Chapel. They will be waved off on their carriage procession through Windsor by members of both families. The congregation will file out of the chapel to see the newlyweds leave before heading to St George's Hall for the lunchtime reception hosted by the Queen.
The carriage procession through the streets of Windsor is expected to take about 25 minutes
The Queen's reception is not being televised and neither is the evening reception at Frogmore House, but viewers will get another glimpse of the royal couple when they leave Windsor Castle at 7pm for the reception, which is hosted by the Prince of Wales.