Bosses at the 'Camfed: Back to School Shop' work to raise funds for education supplies including stationery and uniforms, as well as six-month or one-year bursaries for impoverished students in the region.
Watson, who showed her support for the causes in 2009 by launching her own ethical clothing range in aid of fair trade fashion charity People Tree, has thrown her weight behind the campaign.
"Please help CamfedUK with their campaign to give that one thing their students need to go to school," she posted on Twitter.