The early frontrunner for next year's presidential election in Mexico, Enrique Pena Nieto, has formally registered his candidacy.
Mr Pena Nieto is standing for the opposition Institutional Revolutionary Party (PRI), which governed for 71 years before losing power in 2000.
Hundreds of supporters cheered as he promised to transform Mexico, creating jobs and improving public security.
The governing conservative PAN party has yet to choose its candidate.
Mexico's constitution prevents President Felipe Calderon from standing for another six-year term.
The left-wing Party of the Democratic Revolution (PRD) will be represented by Andres Manuel Lopez Obrador, who came a narrow second to Mr Calderon in 2006 and refused to accept the result.
Mr Nieto, 45, is often described as Mexico's most handsome politician.
In September he stepped down as governor of the state of Mexico, the country's most populous state, where he gained a strong support by delivering public works.
'Wind of change'
After registering his candidacy in Mexico City, he told supporters that the PRI could deliver positive change.
"Today in Mexico there is fear, but better times are coming," he said.
"A wind of hope and change is blowing: the PRI will restore the greatness of Mexico because we believe in solutions, not illusions."
Opinion polls put Mr Pena Nieto 20 points ahead of any challenger, though there are still eight months to go before the election in July.
His popularity has been boosted by his personal life story.
In 2007 his wife suddenly died, leaving him a widowed father of three.
In 2010 he remarried to a soap opera star Angelica Rivera, in what was dubbed a "fairytale" wedding.
The election campaign is likely to be dominated by debate over how to combat drug-related violence, which has killed more than 40,000 Mexicans since Mr Calderon became president in December 2006.
Mr Nieto has called Mr Calderon's decision to use the army against drugs cartels "rushed and poorly planned," but he has not said if he would take the troops off the streets.