Nigerias presidential election was shaping up to be a contest between two veteran male politicians, but the candidacy of Oby Ezekwesili could change that.
Women have run for the presidency before but she is the most prominent Nigerian woman to challenge for the top job, the BBCs Nigeria reporter Chris Ewokor says.
Ms Ezekwesili is well known for leading the #BringBackOurGirls campaign to help free the 276 girls kidnapped from Chibok, northern Nigeria, in 2014. She has also served as the countrys education minister and vice-president of the World Bank.
But come Februarys vote it will be a tough challenge to unseat incumbent President Muhammadu Buhari, 75, or beat the main opposition candidate, Atiku Abubakar, 72, who both have formidable party machines behind them.
The deadline to register for the election passed at midnight local time (23:00 GMT) on Sunday and at least nine candidates in all are thought to have submitted their papers.
At the weekend, President Buhari was nominated by his All Progressives Congress (APC) and Mr Abubakar beat a field of 11 others to become the flag bearer for the Peoples Democratic Party (PDP).
The two parties have supplied all of Nigerias presidents since the end of military rule in 1999.
What is Oby Ezekwesilis message?
For Ms Ezekwesili the men she is facing represent a mediocre political class that bumbles from one crisis to another, as she told the meeting of the Allied Congress Party of Nigeria (ACPN), where her candidacy was declared.
She is setting herself up as the anti-establishment candidate, calling the politicians in charge of the country part of an evil ruling class. And, in an Obama-like move, the ACPN is labelling her as the hope candidate.
Ms Ezekwesili, who is 55 years old, is also trying to appeal to the youth of the country, saying that the people in charge do not understand the technological changes that are happening.
More than 50% of Nigerians are under the age of 30.
How can a country gifted with millions of young, vibrant, brilliant people, be satisfied with just being [an] onlooker? she asked.
Can she disrupt the election?
Chris Ewokor, BBC Africa, Abuja
Along with reaching out to Nigerias youth, Ms Ezekwesili has an obvious appeal to women, and her high profile in the country and international respectability could also boost her candidacy.
She is also from the south of the country, while the two leading men are from the north, so this could help her pick up votes among southerners who want one of their own to lead the country.
Ms Ezekwesili is likely to elicit some support and could make the APC and PDP nervous, but the power of the established parties may be hard to overcome.
Many in the country are hungry and live under extreme economic pressure and could be tempted to back parties with deeper pockets if they are promised money to vote a particular way.
The APC and PDP have countrywide structures and a war chest that could clearly outspend Ms Ezekwesili.
In response, her party has launched a funding campaign to try and build up its financial resources, but it is not clear if that will be enough.
What is Atiku Abubakar saying?
The main opposition candidate is turning his fire onto the countrys current leadership.
The task to get Nigeria working again starts now, he tweeted after he won the PDPs nomination.
Mr Abubakar, a powerful political figure and wealthy businessman, fought off a strong field including the leader of Nigerias senate, Bukola Saraki, to get the nomination.
He served as vice-president from 1999 to 2007 and has made several attempts to run for the presidency, but has only once before secured the nomination of a major party.
He ran for Action Congress, a precursor to the APC, against the PDPs Umaru YarAdua and Mr Buhari in 2007. Mr Abubakar gained 7.5% of the vote but complained of widespread fraud.
BBC