The Queen is due to be driven down the course in an open-top car, there will be a Red Arrows display and Katherine Jenkins will
sing the National Anthem.
The weekend's main celebrations include the Thames
pageant involving 1,000 boats on Sunday, and Monday's concert in front of
Buckingham Palace. There will be events UK-wide to mark 60 years since
the Queen's accession.
On the final day of the weekend, the Queen will attend
a national service of thanksgiving at St Paul's Cathedral, before thousands of
well-wishers are expected to line the route of a formal carriage procession
back to Buckingham Palace. The Royal Family will then make a balcony appearance
at the palace.
On Friday, roads in central London were closed in the
early hours as members of the armed forces and the Household Division were
among 2,000 servicemen and women rehearsing the carriage procession from
Westminster Hall.
And crews of the 1,000-strong flotilla that will
escort the royal barge along the Thames on Sunday were briefed.
The start of the celebrations was signalled by a
21-gun salute from Royal Navy warship HMS Diamond, in Portsmouth, Hampshire.
And tributes were paid to the Queen on Friday by Prime
Minister David Cameron and the Archbishop of Canterbury Dr Rowan Williams.
In an interview with Sky News, Mr Cameron said: "
What I see in Her Majesty is someone - in spite of the fact she's been on the
throne for 60 years, in spite of the fact that her and Prince Philip are now
relatively elderly - there is an extraordinary level of physical energy, mental
energy, and above all devotion to her people, to the institutions of this
country, to the way our democracy works."
Dr Williams issued a video tribute to the Queen,
praising her as "someone who can be friendly, who can be informal, who can
be extremely funny in private - and not everybody appreciates just how funny
she can be - who is quite prepared to tease and to be teased, and who, while
retaining her dignity always, doesn't stand on her dignity in a
conversation."
Beacon lighting
Millions of Britons are expected to take part in
Jubilee parties, outdoor concerts and fairs being staged across the country
over the weekend.
On Sunday, in what is being called the Big Jubilee
Lunch, people all over the UK are being encouraged to share lunch with
neighbours and friends in street parties or picnics to bring communities
together.
Monday's concert, in front of Buckingham Palace in the
area surrounding the Queen Victoria Memorial, will see performances from
artists including Dame Shirley Bassey, Sir Elton John, Jessie J, JLS and Ed
Sheeran.
The concert will be broadcast live on BBC One, BBC One
HD and on BBC Radio 2 in the UK and to millions around the world.
When it ends at 22:00 BST, more than 4,000 beacons are
due to be lit in the UK and around the world.
The Queen lights the UK's last beacon - the National
Beacon - at about 22:30 BST, to be followed by a firework display at Buckingham
Palace.
The weather forecast is poor for the official
celebrations and street parties in the south of England.
Light rain is expected on Saturday, while the next
day's Jubilee river pageant along the Thames could be doused in rain with
temperatures reaching a high of 11C, according to BBC Weather.
The north of England and Scotland are the most likely
areas to avoid the rain.