Malawian musician-turned-politician Lucius Banda has been sentenced to 21 months in jail with hard labour for faking his academic qualifications.
Lucius Banda believes he has been made a scapegoat
The opposition MP moved a motion in parliament last year proposing procedures to impeach the president.
Shortly afterwards, the authorities arrested him over allegations that he forged a school certificate that enabled him to stand for parliament.
Mr Banda told the BBC after the verdict that he has been made a scapegoat.
The BBC's Raphael Tenthani says the courtroom in Zomba, some 70km from the commercial capital, Blantyre, was packed with fans of Mr Banda who is popularly known as the "Soldier of the Poor".
"You are supposed to be a role model for the youth and Malawians take education seriously and by forging the Malawi School Certificate for Education you betrayed the trust of many," magistrate Luke Mabowoza told Malawi's top selling artist.
The jail sentence means that Mr Banda will lose the seat in parliament he won in 2004.
"I know the government is punishing me for the motion I moved [in parliament] but I don't regret it," Mr Banda told the BBC's Focus on Africa programme after his conviction.
"I am actually proud of myself and I hope the whole nation knows I did nothing wrong to set procedures for impeachment of a president."
Our correspondent says as Mr Banda was driven away in a police vehicle, scores of his supporters shouted insults at the police, while his aunt and other family members wept uncontrollably.
Mr Banda shot to fame when he released music denouncing the rule of the late Hastings Kamuzu Banda, our reporter says.
When the long time ruler lost Malawi's first multi-party elections in 1994, the musician continued his music crusade by criticising Hastings Banda's successor, Bakili Muluzi.
But the musician then entered parliament as a member of Mr Muluzi's United Democratic Front (UDF) party.
He has since released two albums criticising Mr Muluzi's successor, President Bingu wa Mutharika, who quit the UDF after falling out with Mr Muluzi.