Businessman Saki Macozoma, a former rising star in the ANC, deliberately delayed his defection to COPE to avoid accusations that the party is a vehicle for angry allies of former president Thabo Mbeki.
Macozoma, after months of speculation and denials, was finally paraded as a member in Port Elizabeth, where presidential candidate Mvume Dandala went on his first walkabout and also addressed a rally on Saturday.
"I wanted it to be clear that COPE was formed by people who want a new agenda, not a situation where Thabo Mbeki's allies are organising people against the ANC," he said.
The ANC previously accused Macozoma of funding COPE, and there had been growing calls for his expulsion from the ruling party.
Macozoma said one reason he decided to come out publicly was that he was now finally convinced that the ANC had deviated from the ideals for which it was formed.
"It is important for people to have a feeling of a grassroots response to a serious political problem, the deviation of the ANC from the ideals of the movement."
Macozoma said COPE was not, as some would like to believe, a platform for careerists who wanted to use it to return to the "feeding trough".
"I do not believe so. COPE has brought together a lot of people who had nothing to do with the ANC. The problems in the ANC leadership have brought out young people and women who share a sense of outrage about the behaviour of ANC leaders," he said.
Macozoma also dismissed as "tribalist" assertions that COPE, through its nomination of Dandala as presidential candidate, could be entrenching the notion that only Xhosas are capable to lead.
"If there is an injection that Xhosas need not apply (for leadership positions), that would be tribalist."
The former political prisoner said he did not believe his massive business interests would be in danger now that he has come out as a COPE member; this in the wake of troubles that have befallen others once their links to COPE became known.
"I cannot be an underground supporter because I fear people who might want to target me. What about civil servants who are vulnerable but have taken a stand to join?" said Macozoma.
Dandala told about 1 000 members in Port Elizabeth on Saturday that South Africa was regarded as a beacon of hope for the rest of the continent after 1994, but now people were asking what went wrong.
Dandala said he was in constant communication with "many professionals" who wanted to join COPE but were afraid of losing their jobs.
On Sunday COPE confirmed that former deputy president Phumzile Mlambo Ngcuka had officially joined the party, ending months of speculation.
She has indicated that, while she will campaign for the party, she is not keen to hold a leadership position.