South Sudan President Salva Kiir has reappointed bitter rival Riek Machar as vice-president as part of a peace deal aimed at ending more than two years of war, according to the BBC.
The move returns the government to where it was before the war broke out.
The civil conflict erupted in December 2013 after Kiir accused Machar of plotting a coup.
Since then thousands have died and more than two million have been displaced.
South Sudan is the world’s youngest country and one of the least developed. It split from the North in 2011.
Amid a threat of sanctions from the UN, the two sides signed a peace deal in August last year.
Fighting was supposed to stop immediately but there have been frequent violations.