In a surprise decision, Taiwan's high court Friday cut ex-president Chen Shui-bian's life sentence for corruption to 20 years in jail, but the former leader said he would appeal.

The court, which also reduced former first lady Wu Shu-chen's life term to 20 years imprisonment, said it had reached the decision after concluding that Chen had embezzled less money than previously assumed.

"I thank the judges for the lighter sentence, but I will still appeal the ruling," said Chen, looking thinner and sporting longer hair than during his heyday as president from 2000 to 2008.

Chen was speaking after his reduced sentence was announced, while taking part in a detention hearing.

The court said it would give Chen a written reply later about whether it planned to keep him in detention while he prepared his appeal.