Prince Seeiso Bereng Seeiso of Lesotho spent yesterday afternoon in Rotherham, where he visited pupils at the town's St Bernard's Catholic High School.
Youngsters at the school are planning a trip to the nation, in southern Africa, next year. The prince also visited Rawmarsh-based printing firm B&B Press.
Staff at the company have provided cash to plant thousands of trees in Lesotho as part of a scheme to offset their energy use and carbon footprint.
This morning the prince was set to meet pupils at Sheffield's City School and Sheffield Council leader Paul Scriven, to launch the new Trees4Africa project.
Trees4Africa aims to plant one million trees in Lesotho by 2015 and is being co-ordinated by Sheffield-based Connecting Communities Worldwide, a social enterprise which has been set up by the City School's former assistant headteacher Ken Dunn.
Connecting Communities Worldwide is a not-for-profit company which aims to help schools in the region build links with Lesotho, both to help the country and provide educational opportunities.
Mr Dunn said: "It is a great honour to have two high-profile people involved in the initiative. Tree planting in Lesotho is extremely important as the different tree species will in turn provide fruit, prevent soil erosion and absorb CO2.
"In the case of the indigenous Cheche tree they will also provide fuel wood for communities in the country."
Mr Scriven and the prince, who was educated at Ampleforth School in North Yorkshire, were set to plant a tree in the grounds of City School today to mark the start of the project.
Pupils from South Yorkshire schools and students from Sheffield University will travel to Lesotho next year to plant the trees.
Anyone who would like to plant a tree in Africa as part of the scheme should contact Trees4Africa on 07402 090108 or visit the Connecting Communities Worldwide website at www.ccwltd.org for more information.