Joss Stone, Ms Dynamite and Lemar helped set a new singing record for the largest number of children singing simultaneously today.
Big Sing featured 502,000 children, who were also raising money for UK children’s cancer charity CLIC Sargent and the African Children’s Choir.
The existing Guinness World Record featured 83,637 children and was achieved three years ago.
Soul singer Stone, Lemar and Ms Dynamite led the youngsters in a rendition of Lean on Me at the Royal Albert Hall.
Children at schools across the country sang along as the proceedings in London were broadcast on local radio.
The event, which will be followed by a concert tonight at the Royal Albert Hall, was co-ordinated by Young Voices, an organisation which aims to encourage choral singing in schools.
A Big Sing spokeswoman said: “We have had 502,000 children registered to take part in the singing.
“Witnesses will be signing declarations for the number of people taking part, which will be sent on to Guinness World Records.”
The African’s Children’s Choir, who were also at the Royal Albert Hall, help children in Africa who have suffered as a result of war, sickness or poverty.
The event is expected to raise £500,000 (€740,000).