Lapiro often sings about government corruption
One of Cameroon's best-known singers, Lapiro de Mbanga, is going on trial, accused of organising anti-government riots earlier this year.
The riots left more than 100 people dead after the army and police put down the protests.
Lapiro's supporters say he is being victimised because of his songs, which often criticise the government.
Following controversial changes to the constitution, he released a song called "Constipated Constitution".
The changes pave the way for President Paul Biya, 75, to seek re-election in 2011.
He has been in power for 26 years.
Lapiro has already spent 90 days in custody and could face a two-year prison term, if found guilty of being behind the riots in his home town of Mbanga, north of the economic capital, Douala.
His wife said Lapiro, who is in his 50s, had lost 20kg since his arrest in April.
The BBC's Jean-David Mihamle in Cameroon says the trial comes as more than 100 of those arrested during the riots have been pardoned by the president.
He says the authorities fear protests by opposition supporters and Lapiro's fans and have tightened security outside the court in the regional capital, Nkongsamba.
The singer is a member of the opposition Social Democratic Front and has often sung about government corruption.