Ahead of tonight's Olympic opening ceremony, the Prime Minister said the country must show the world "the best of Britain" over the next two weeks.
"We have got a great past, a very exciting future and this is a great moment for our country, so we must seize it," he said.
His comments came as the Olympic torch continued on the final leg of its 70-day, 8000-mile journey around the United Kingdom, which will end when it arrives at the Olympic Stadium for tonight's opening ceremony.
The torch, which has snaked its way through the UK and been seen by millions of excited spectators, was taken down the Thames on the royal rowbarge, the £1million Gloriana.
Later, the flame will be carried into the stadium where a ceremonial cauldron will be lit by a mystery VIP.
The last land-based torch bearer was four-time Olympic gold medalist Matthew Pinsent, who carried the flame from London's Hampton Court Palace to the Gloriana.
Rowers young and old, ranging from members of London Youth Rowing to two men in their 90s who took part in the 1948 Games, are taking it in turns to man Gloriana's 16 oars. The rowbarge, accompanied by its mini flotilla of boats, was given three cheers from those watching on the banks before it set off.
Efforts to keep the highlights of the £27m opening extravaganza a secret have also been stepped up, with footage of last night's dress rehearsal removed from YouTube.
Some bookmakers have closed betting on Sir Roger Bannister, the first man to run a mile in less than four minutes, being chosen to light the Olympic Flame at the opening ceremony.
Sir Steve Redgrave and Daley Thompson are also among the favourites to take the honour, but the identity of the person who will light the cauldron will remain a secret up until the final moment.
The ceremony has yet to sell out, with some tickets still available for more than £1500.
The Olympic flame visited Buckingham Palace yesterday, witnessed by the Duke and Duchess of Cambridge. It also travelled to Trafalgar Square, Downing Street and London's West End.
Sir Bruce Forsyth carried the torch at the site of the finishing line of the first ever London Games, outside the BBC's White City studios in west London, which stands on the site of the stadium that hosted the 1908 Olympics. Sir Bruce, 84, called out his catchphrase: "Nice to see you, to see you, nice."
Last night, the torch was used to light a giant cauldron in Hyde Park, where 80,000 people had gathered for an Olympic gig.
The event was headlined by Dizzee Rascal, alongside local London talent including Tottenham rapper Wretch 32, Katy B and Eliza Doolittle.
Meanwhile First Minister Alec Salmond has sent a good luck message to Scotland's 54 Olympians and 23 Paralympians saying: "The eyes of the world are on the Olympics and the whole of Scotland is united in supporting our Olympians and Paralympians – our 'Scolympians' – to go for gold."
