London, England (CNN) -- Nelson Mandela and Graca Machel have been crowned the "Decade Child Rights Heroes" in a vote cast by children from all over the world.
Over seven million children participated in the vote who were asked to choose from a shortlist of 13 candidates.
All of the nominees had previously won the annual World's Children's Prize which is organized by TheWorld's Children's Prize for the Rights of the Child (WCPRC) -- the world's largest educational program promoting young people's rights.
Mandela and Machel, who married in 1998, jointly won the World's Children's Prize in 2005 and were recognized for the enormous contributions they have made in promoting the rights of children in their respective homelands.
In a joint statement Mandela and Machel said: "We are extremely honored to have been voted as the Decade Child Rights Heroes. For both of us this award is very, very special given the place children occupy in our hearts and lives."
Mandela, 91, was praised for his life long struggle for equal rights for the children of South Africa while Machel was honored for her 25-year fight for the rights of vulnerable children in Mozambique. Their prize of one million Swedish Krona ($1 million) will help them continue their work promoting children's rights.
The announcement of the winners, which was made by children in a series of press conferences in India, Sweden and South Africa, was timed to coincide with the 20th anniversary of U.N. Convention on the Rights of the Child.
Since 2000, the annual World's Children's Prize has awarded prizes for outstanding efforts in establishing the rights of children. In total there have been 27 recipients (three each year) of the award.
Previous winners who were shortlisted for the Decade Child Rights Heroes prize included Maiti Nepal who fights the trafficking of girls from Nepal to India, where they are forced to work in brothels.
Ethiopian nominee, Asfaw Yemiru opened his first school for street children when he was just 14 years old. Since then he has devoted over half a century to helping underprivileged children.
Iqbal Masih from Pakistan, who was recognized posthumously, was a debt slave in a carpet factory who fought for the rights of debt slave children during his life. He died in 1995.
With the help of over 50,000 teachers and around 500 organizations the WCPRC helps give a platform for the voices of 23 million children from 53,000 schools in 101 countries educating them about child rights and democracy.