Cape Town — A joint technical committee will manage the integration of the DA and Agang SA structures and volunteers, DA leader Helen Zille said on Tuesday.
"This is a game-changing moment for South Africa," she told reporters in Cape Town.
Zille said that when she was elected Democratic Alliance leader in 2007 she set out a case for the realignment of politics in the country.
"I said then that political change will come about as the old political formations become obsolete. We can see this happening now."
Zille announced earlier that Agang SA leader Mamphela Ramphele would be the DA's presidential candidate in the upcoming general elections.
She said the DA's leadership was drawn from across the political spectrum but they shared the same values, "the belief in an open-opportunity society for all characterised by non-racialism, a market economy, human rights and prosperity for every South African".