EDF and Centrica are set to build new nuclear power stations alongside existing reactors at Sizewell in Suffolk and Hinkley Point in Somerset.
The firms have formed a partnership to develop at least four power plants in the coming years.
We are delighted to have successfully concluded an agreement with EDF as a world leader in nuclear power," said Roger Carr, chairman of Centrica.
He added: "The deal represents good value for Centrica shareholders, improves the strategic balance of our business and further underpins our green energy credentials."
The joint venture announcement comes hot on the heels of Centrica's announcement that it has taken a 20 per cent £2.3 billion stake in British Energy, which is owned by EDF.
Meanwhile, EDF will take ownership of Centrica's 51 per cent stake in Belgian electricity generation firm SPE.
Centrica paid £490 million for its controlling share of SPE in July of last year.
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