Marina Silva has been confirmed as the new presidential candidate for the Brazilian Socialist Party.
The announcement comes one week after the previous candidate Edwardo Campos was killed in a plane crash.
Silva was Campos’s vice-presidential running mate and the decision for her to replace him was widely expected.
“I feel that the Brazilian Socialist Party will take forward the plans for the future that were inspired by Eduardo Campos,” said Silva after the announcement.
Before his fatal plane crash, the 49-year-old former governor was a rising political star with the support of about ten percent of voters.
Polls put Santos in third place behind President Dilma Rouseff and conservative candidate Aecio Neves.
But polls since Campos’s death have shown Silva is neck and neck with Neves.
One poll has suggested that if the vote goes to a second round run-off Silva could beat President Rousseff by four points.
Brazil’s presidential election is set for 5th October.