Prime Minister David Cameron will lead a show of solidarity with France at an England-France soccer match in London on Tuesday following the bloody attacks on Paris, with English fans expected to sing the French national anthem.
Cameron, Prince William and London Mayor Boris Johnson will attend the friendly match at Wembley Stadium and armed police, a rare sight in Britain, will guard the event.
Explosions were audible as Islamic State militants targeted a friendly between France and Germany attended by French President Francois Hollande in Paris on Friday, one of a wave of attacks that killed at least 129 people.
A French player lost his cousin in the violence and the side stayed overnight in the Stade de France with the German team as a security precaution, but the French soccer federation said the England game should go ahead for symbolic reasons.
Cameron said on Tuesday that it was important for Britain to stand side-by-side with its neighbour, which was also targeted by Islamist militants in January.
"Now, more than ever, we must come together and stand united and carry on with the way of life that we know and that we love," he told parliament. "This match is going ahead."
English fans are expected to put aside traditional football rivalry and sing the French national anthem, the Marseillaise, at the match that is due to begin at 2000 GMT.
Police urged supporters to arrive early due to additional security searches and said there will be "extra, highly visible, armed officers" patrolling around Wembley.
Common in European countries like France, armed police are generally rarely seen in Britain although they did patrol the London Olympic Games in 2012 and have taken on more of a profile in recent years due to fears of Islamist militancy.
A match between Belgium and Spain due to take place in Brussels, where police have carried out raids in the wake of the Paris attacks, has been postponed for security reasons after the government advised against going ahead.
Ahead of the Wembley match, French coach Didier Deschamps said his side would play England with "even more pride" and England manager Roy Hodgson said the match would be like no other he had played before.
"I really can't imagine how this game is going to go and what sort of football is going to be played, quite simply because I've never been in this situation before," he said.