Singer-actor Cha Eun-woo has filed an appeal against the National Tax Service (NTS), after paying some 13 billion won ($9 million) in additional taxes earlier this year, Cha's agency said Sunday.

Cha submitted the appeal with the Tax Tribunal last month, claiming the NTS decision ordering him to pay the amount in additional income tax assessments was unfair, Fantagio said.

"Cha filed the appeal to receive a legal assessment, in accordance with the procedures established by law," the agency said, without providing further details.

By law, a taxpayer is eligible to submit an appeal with the tribunal within 90 days of receiving a tax bill in the event it is deemed unlawful or unfair.

In January, Cha was reported to have been notified by the tax service of additional income tax assessments exceeding 20 billion won, raising suspicions of tax evasion.

In April, the singer-actor said he paid off all related taxes so that confusion surrounding the case does not continue, adding he respects the NTS' procedures and outcome.