Jordan "Rizzle" Stephens, one half of the Rizzle Kicks, said the concert would help explain Stephen Lawrence's murder and the events surrounding it to a younger generation like them who were not born or were very young when he died.
He said he hoped it would help challenge negative mindsets both in the black community and the wider public.
"What I love especially about this charity and trust is the whole idea of being able to achieve something that you wouldn't ordinarily think you could do," he said.
He added: "A lot of statistics are made based on the fact that some youths are convinced they can't do something they are very capable of doing."
He also spoke of an incident when he was on a school visit to Chichester, where a woman had assumed because he spoke eloquently that he went to a private school, and was surprised to find he went to a state school in London.
"It upset me that a woman would question intelligence base on my skin colour," he said.
"It would make me more happy than anything for there to be no question about whether race correlated with intelligence, drive or motivation.
"Stephen was an example and the idea is to build as many of those examples as possible for those judgmental idiots."
Multi-award winning Scottish singer Sande said that Stephen Lawrence's murder and Mrs Lawrence's subsequent campaigning had had a bid impact on her family.
"I was quite young when it happened but coming from a mixed-race family it was a big issue that we spoke about, and (we also spoke about) the issues you face being mixed race and this being something that happened in our country.
"It had a big impact on my family and all the work Doreen has done has felt very empowering - that you can speak out about these things and changes can be made if you are brave enough to stand up."
Mrs Lawrence said the money raised by the concert would help her foundation, which has struggled for funding in recent years, to continue its work for another 20 years.
Speaking after the launch event at Abbey Road studios, she said that she would like to see the Government provide more funding.
She said they had received some emergency funding from the Home Office, but added "we shouldn't have to do that".
"We shouldn't have to think 'that's just a one-off'. They should look to continue to do it," she said.
"They have seen the work that we do, they have seen the progress we have made, they have seen all the opportunities that young people have had since they have been at the Stephen Lawrence Centre.
"I think that should be something that makes them say: 'Ok, we want to support an organisation like you, you can make a difference to so many young lives, get them off the streets, get them into education, get them into a profession.'
"That is what I would like to see the Government do a lot more of."
The O2 event will raise funds for a trust set up in Stephen Lawrence's name to help young people from disadvantaged backgrounds.
Plan B, Jamie Cullum, Jessie J, Tinie Tempah and Ed Sheeran are also among the stars taking part in the show on September 29 designed to champion young people.
Stephen's mother, Doreen Lawrence, who founded the trust, said: "We work every day to empower youth and we're so proud that the music industry is joining us in reaching out to change the lives of young people.
"I want young people to feel inspired, be confident and have hope in their own future.
"There have been a further 106 racist murders since Stephen was killed 20 years ago and there are still too many young people who do not have a sense of hope."
Stephen was 18 when he was stabbed in a racist attack in Eltham, south east London, in April 1993. Two men - Gary Dobson and David Norris - were found guilty of the murder last year and the police investigation still remains "live".
The Metropolitan Police were criticised for their handling of the initial investigation and, as a result, the force was judged to be institutionally racist in a subsequent public inquiry.
The show, Unity: A Concert For Stephen Lawrence, has been backed by London Mayor Boris Johnson. Artists also include Rudimental and Soul II Soul.