In the region of 100,000 people are expected to descend on Windsor on Saturday for the wedding of Prince Harry and Meghan Markle.
Here's the key information to get you through the day:
- WHAT TIME WILL IT KICK OFF?
11.20am: Members of the Royal Family will begin to arrive at the church - some by foot, others by car.
At about the same time, Ms Markle will leave their overnight location.
11:45am: Prince Harry and his brother and best man, Prince William, are expected to arrive.
Noon: The wedding ceremony will take place at St George’s Chapel at Windsor Castle.
1pm: The newlyweds will leave Windsor Castle by carriage for the post-wedding procession.
- HOW CAN I GET THERE BY CAR?
Road closures and diversions will be in place and security teams will be stationed around Windsor, so don't expect a smooth trip.
A 6,000 space pre-booked car parking area at the Review Ground, around a 15=minute walk from the Long Walk spectator area.
It will be accessible from 4am but must be pre-booked, with a charge of £30.
Parking can also be booked at the Windsor Racecourse, and parking is available at The Windsors Boys' School on a first come, first served basis.
There's also a coach car park, dedicated taxi drop off and collection areas and cycle storage spaces.
Anyone who has not pre-booked parking is advised to avoid driving into central Winsdor.
- WHAT ROADS WILL BE CLOSED?
From 10pm on Friday, the following road closures will be in place along the procession route:
Castle Hill, High Street, Sheet Street, Kings Road, Park Street, St Albans Street, Market Street, Queen Charlotte Street, Thames Street, River Street, Brook Street, Windsor Greys Roundabout A308 (Peanut roundabout), Albert Road A308
Further closures will then be put in place from 6am on Saturday:
Maidenhead Road, Clarence Road, Alma Road, St Leonards Road, Frances Road, Barry Avenue, Datchet Road
Thames Valley Police has warned that more closures could be rolled out depending on crowd numbers.
- HOW CAN I GET THERE BY BUS?
A designated pick up and drop off point will be set up for buses travelling in to and out of Windsor at St Leonards Road.
- HOW CAN I GET THERE BY TRAIN?
Rail operators will be running extra services - but make sure to catch an early train and allow plenty of time for the journey.
Queueing systems will be in place at some of the key stations linking to Windsor, including: London Waterloo, Clapham Junction, Paddington, Staines and Slough.
Both Great Western and South Western Railway will be increasing train frequency and capacity, with trains running up to four times an hour and with extra carriages.
From Waterloo, direct 10-carriage trains will be run every hour at -:20, -:28, -:50 and -:58.
- WHERE IS THE PROCESSION ROUTE?
After the ceremony, the newlyweds will embark on a carriage procession, commencing at 1pm along a route including Castle Hill, High Street, Sheet Street, Kings Road, Albert Road, Long Walk and finally Windsor Castle.
The carriage procession is expected to take just under 25 minutes.
Watch: The route of the procession
- WHERE CAN I GET THE BEST VIEW?
When Ms Markle leaves for the wedding, she will travel to the Castle via part of the Long Walk, giving members of the public there the chance of an early glimpse.
She will also stop briefly at the Castle, where she will be joined by some of the bridesmaids and page boys before continuing on to the church, where she will enter via the West Steps.
If you're stood along the Procession Route, you stand a good chance of seeing the couple up close too.
Viewing areas will be set up along the whole route (Castle Hill, High Street, Sheet Street, Kings Road, Albert Road and the Long Walk).
Big screens showing live footage of the wedding and the procession will be set up on the Long Walk and in Alexandra Gardens, along with food stalls and facilities.
- WHAT SHOULD I BRING?
It's likely to be a long day, so take food and drink, or cash to buy some from the food stalls along the viewing areas.
Alcohol is permitted.
You're also welcome to take a folding chair and an umbrella in case it rains, but visitors are asked not to take a tent.
In addition, police have urged people not to throw confetti.
- WHAT SECURITY MEASURES WILL BE IN PLACE?
Both armed and unarmed officers will be out and about, as will search dogs and mounted police.
Barriers to prevent car or van attacks have been put in place, known as Hostile Vehicle Mitigation barriers, and officers have ramped up the use of CCTV and automatic number plate recognition.
They will be stopping vehicles en route into Windsor on the day, and will be carrying out random searches.
Thames Valley Police has asked that anyone who spots anything they believe might be suspicious to contact an officer immediately.
- WHAT ABOUT LEAVING AT THE END?
The roads are likely to be extremely busy, and many road closures will still be in place until late, so you can expect to be sat in traffic for while.
For those travelling by train, there will be a queuing system in place at both Windsor & Eton Riverside and Windsor & Eton Central.