The rock band Queen declared the Hyde Park concert will be a tribute to all the victims of the terrorist attacks, but also for the police, firefighters and ambulance staff for their extraordinary efforts after the London bombings.
The band was scheduled to play last Friday in Hyde Park, London, but the concert was postponed for this Friday, due to Thursday's terrorist attacks.
In a statement, Queen's new frontman Paul Rodgers said: "We feel it is fitting to thank London's emergency services for their extraordinary response in dealing with the effects of the bombing attacks and to celebrate the historical resilience of Londoners in their response to yet another atrocity."
Rodgers, the former singer of the 1970s band Free, has been singing in place of Freddie Mercury, who died in 1991.
Guitarist Brian May said: "We were away playing a concert in Germany and arrived back Thursday morning to see all this going on. We were unbelievably shocked and saddened.
"The heroes that day, and since then, are the police and emergency services coming together as one, calmly and bravely dealing with the tragedy and getting London's wheels turning again. We'd like to offer an appreciation."
More than 85,000 fans are expected to attend the concert, this being the first time after 29 years for Queen to play in Hyde Park.
Comic Peter Kay, young rockers Razorlight, and Justin and Dan Hawkins from the neo-glam band The Darkness will also be present at the show.