De Beers has spoken out in favour of a £12 billion takeover bid by a newly-formed consortium.
Following the transaction, 45% stakes in De Beers will be owned by CHL, a holding company for the interests of South Africa's Oppenheimer family, and by the mining firm Anglo American.
The remaining 10% will be owned by Debswana, a company jointly owned by the government of Botswana and De Beers which operates three diamond mines in Botswana.
Nicky Oppenheimer will continue to be executive chairman of De Beers, and will chair its new parent company called DB Investments or DBI.
The deal is subject to competition and regulatory approvals, and will need the go-ahead from shareholders.
De Beers says that under DBI's ownership, it will benefit from the "commitment and leadership of the Oppenheimer family", and from Anglo remaining a major shareholder.
It says it will also benefit from forging a closer relationship with Debswana and the government of Botswana.
The deal will simplify Anglo American's structure by removing the cross-shareholding which sees it owning 32.2% of De Beers, which in turn owns 35.4% of Anglo. Under the terms of the proposed deal, Anglo's stake in De Beers would be increased to 45%.
And it says the deal would provide immediate foreign funds inflow to South Africa estimated at £2bn, as well as demonstrating "confidence in the new South Africa by a group and a family that have played a leading role in South Africa's economic development for more than a century".