Building bridges between Muslims and the wider community is one of the aims of a four-day event in London about the faith, organisers say.
Former Iraq hostage Norman Kember will speak at IslamExpo
The Muslim Association of Britain (MAB) said it wanted to attract a wide range of visitors to IslamExpo.
Mayor Ken Livingstone, Lord Coe and Yusuf Islam - formerly Cat Stevens - will open the event in London, which is expected to attract 40,000 people.
Among those due to speak is former Iraq hostage Norman Kember.
'Islam no threat'
A two-minute silence at midday on Friday, in memory of the victims of the 7 July bomb attacks, will be observed at the event in Alexandra Palace.
But organisers said the festival had been planned since 2002 and had coincided with the anniversary of the attacks by chance.
A series of exhibits on Islam, lectures, debates, films and concerts will feature in what MAB said was the biggest event of its kind ever staged in Europe.
An economic conference will also be held as part of the festival - in Canary Wharf - to promote London as a centre of investment for the Islamic world.
Spokesman Anas Altikriti said IslamExpo was not just targeted at Britain's 1.8m Muslims.
"The hope is that all kinds of people will visit and go away thinking about things, and not that Islam is a danger or a threat," he said.
Ihtisham Hibatullah of MAB said the event would see mainstream Muslims "condemning terrorist atrocities taking place in London and elsewhere against innocents".
"The focus on Friday will be to share in the sorrow of the families of the victims and the survivors. There will be a strong message from the mainstream Muslim community against all violence by extremists."
Mr Altikriti, chief executive of the Cordoba Foundation, visited Iraq in an attempt to secure the release of Christian peace activist Mr Kember.
The pair will share a platform for the first time on Friday.
Other speakers include BBC security correspondent Frank Gardner, who survived an assassination attempt while filming in Saudi Arabia, and former BBC correspondent Rageh Omaar.
This week Prime Minister Tony Blair called on moderate Muslim leaders to speak out more against extremists within their communities.
But Muslim Council of Britain secretary general Dr Muhammad Abdul Bari accused Mr Blair of playing an "unhelpful blame game" by suggesting moderate Muslims were doing too little to challenge extreme views.