Mr. N’Dour has, however, emerged in recent years as an outspoken critic of Mr. Wade, whose years in office have been marked by widespread accusations of corruption, nepotism, constraints on freedom of expression and personal enrichment. Despite those problems, the protests that erupted this summer — complete with tear gas and tire burnings — were unusual in a West African country where power has never been seized in a coup, making it a rarity in the region.

Since the end of European colonialism, musicians have often served as voices of conscience and protest in independent African nations, criticizing corruption and dictatorship. The best-known example was Fela Kuti of Nigeria, the main creator of the Afropop style in the 1970s and a ferocious opponent of military rule in his country.

Still, Mr. N’Dour’s plunge into electoral politics is an unusual move for an African entertainment celebrity. Mr. Kuti announced plans to seek the presidency in 1979 and 1983, but was disqualified both times.

In some other developing countries, especially those in Latin America and the Caribbean, that kind of crossover is more common and accepted, however. The current president of Haiti, for example, is Michel Martelly, a singer known in his performing days as Sweet Micky. He was elected last year in a race in which the rapper Wyclef Jean also threw his hat in the ring, only to be disqualified because he did not meet residency requirements.

In Senegal, the sitting president, Mr. Wade, who gives his age as 85, is already trying to play down his latest rival’s importance and chances. The implication is that Mr. N’Dour, who has sung of the importance of education but began working as a professional musician at the age of 12, has neither the experience, education nor program needed to lead a struggling country of 12.5 million people.

“We’re waiting for all the candidates, including Youssou N’Dour, to detail their policy ideas,” Amadou Sall, a spokesman for Mr. Wade, said, according to Reuters, “and not just list a string of wishes.”

In announcing his candidacy, Mr. N’Dour acknowledged those shortcomings. But he laid claim to other virtues, presenting himself as a self-made man whose standing in the outside world would help bring Senegal attention and investment.