The Diamond Jubilee river pageant welcomed its first royal guests on Sunday as excitement grew ahead of the start of the Diamond Jubilee river pageant.
The Prince of Wales and the Duchess of Cornwall were greeted by cheering crowds when they arrived at Chelsea Pier ahead of the Queen.
Charles is patron of the pageant and first suggested the idea of a water-borne tribute to the Queen.
Fittingly for a day on the river the heir to the throne was wearing his Royal Navy Admiral's ceremonial day dress uniform, while the Duchess was wearing an Anna Valentine coat and dress and a hat by Philip Treacy.
A guard of honour formed of Chelsea Pensioners in their immaculate scarlet uniforms were lined up in front of the royal couple.
Spectators have been given some respite from the rain that threatened to dampen spirits earlier, but forecasters have predicted more wet weather later this afternoon.
Crowds have been building up along the banks of the Thames throughout the capital with a party atmosphere growing.
Charles and Camilla ventured out into the rain earlier to join a Big Jubilee Lunch street party in London's Piccadilly.
The royal couple stopped to chat to revellers in the street and even sat down with them.
London Mayor Boris Johnson was upbeat from Putney Pier, declaring the rain had passed as he geed-up the crowds around him.
"I want you to know the rain has stopped, hasn't it?" the politician said, turning to a crowd behind him while being interviewed by BBC News.
He added: "It's going to be a fantastic day, I've no doubt about that at all.
"We're are looking forward very much here in Putney to the kick-off, which I think is in a couple of hours time, but already the crowds are enormous here."
There was a toot from a nearby ship and more cheers went up as the royal couple walked along the river bank to the waiting Chelsea pensioners.
The Duchess of Cornwall sheltered under a see-through umbrella from the light drizzle and the royal couple shook hands with all the waiting pensioners.
Meanwhile the younger royals - Duke and Duchess of Cambridge and Prince Harry - arrived at nearby Cadogan Pier to board the royal barge - the Spirit of Chartwell.
Kate was dressed in a red Alexander McQueen dress and a Sylvia Fletcher hat from James Lock & Co.
While William, an RAF Search and Rescue helicopter, and Harry, an Army Captain who files Apache helicopters, both wore military uniform.
The three younger royals went on a short walkabout greeting some of the spectators who had waited to catch a glimpse of them.
The pomp and ceremony of the occasion saw trumpeters give a fanfare blast as the royal party walked towards the jetty and heralds lined their last few steps onto a launch.
They boarded the launch of the former royal yacht Britannia and soon after it left its mooring a shrill salute was blown by the London Midland and Scottish Railway Coronation Class steam locomotive on the nearby Battersea Rail Bridge.
Aptly named the Princess Elizabeth, it has been lovingly restored and was inspected by the Queen when she opened a heritage centre in 1987.
A huge plume of steam went up into the air as its whistle was blown several times before the train pulled away.
The Queen and Philip, dressed in the Admiral of the Fleet uniform, stood up as they made the short journey to the royal barge and were cheered for much of their journey by the crowds on the river banks.
The Queen and Philip and Charles and Camilla boarded the lavishly decorated royal barge - the Spirit of Chartwell.
Pageant Master Adrian Evans, the man who has organised much of the event, greeted the royals in turn as they arrived on the upper deck.
Plush red velvet seats with a canopy were in place for the royal party to use.
The first squadron of the flotilla, made up of boats powered by oars or paddles, sped past the royal barge to take up their place ahead of the royal squadron followed by boats carrying flags of all the Commonwealth nations.
Leading the flotilla was a floating belfry sounding a peal of its eight bells, which will be answered by bell towers along the route.
Each has been named after a senior member of the Royal Family with the tenor - the largest - christened Elizabeth and the smallest - the treble - called Henry.
The rowed vessels saluted the Queen by tossing oars - raising their oars in the air - as they passed.