Kgalema Motlanthe, South Africa's deputy president, has agreed to run against President Jacob Zuma for the leadership the country's ruling party, the African National Congress (ANC).
Motlanthe accepted nominations from several provinces and the party's youth league to enter the race to be the ANC's next president, his spokesman Thabo Masebe said on Thursday.
The announcement ended weeks of uncertainty as Motlanthe previously told journalists he was "agonising" over whether to accept the call to challenge Zuma, whose popularity has faded over corruption allegations and questions about his private life.
Motlanthe also accepted nominations to hold onto his current position, as well as to hold another leadership position in the party, Masebe said.
That could put Motlanthe, 63, in position to hold onto his deputy president post even if he loses out to Zuma, 70, for the top spot.
However, others, including business tycoon Cyril Ramaphosa, have been discussed as possible replacements for the deputy position in a bid to push out Motlanthe.
Becoming leader of the ANC means a nearly automatic ticket to becoming the the president of South Africa.
Opposition parties do not garner the widespread support given to the ANC, the party of anti-apartheid icon Nelson Mandela.
The party's president will become the state president, if the ANC wins national elections in 2014, and its deputy president will serve in the same national office.
In many ways, Motlanthe appears to offer almost the opposite qualities of Zuma.
Motlanthe is largely reserved, while Zuma knows how to whip up a crowd.
Motlanthe also appears untainted by the recent corruption allegations that have plagued Zuma and other high-level and local ANC officials in recent years.
Motlanthe previously served as a caretaker leader for South Africa, serving as the nation's president from September 2008 to May 2009 after then-president Thabo Mbeki resigned after being ousted as the head of the ANC by Zuma in a tight election.
However, Motlanthe held back as long as possible before confirming he would challenge Zuma.