A former president and CEO of Nissan Motor Co. on Wednesday testified for the first time in court against the automaker's former chairman, Carlos Ghosn, over his alleged financial misconduct.

Hiroto Saikawa admitted during the trial of Greg Kelly, who was a close aide to Ghosn, that he signed documents outlining Ghosn's post-retirement remuneration in front of his boss. He said he was approached by Kelly around 2011 after Japan strengthened its executive compensation disclosure requirements.

Saikawa said he found it "necessary" to give a generous package to Ghosn to keep him motivated to work for Nissan and prevent him from going to a rival automaker.

Ghosn, who was arrested in 2018 along with Kelly, jumped bail and fled to Lebanon, leaving Kelly to face Japanese justice alone.

Kelly, who allegedly aided his boss to underreport Ghosn's remuneration by tens of millions of yen over several years, is facing charges of violating the financial instruments and exchange law.

Kelly is suspected of having submitted to Japanese authorities financial reports that only listed about ¥7.9 billion as Ghosn's pay even though his actual income totaled about ¥17 billion over eight years through March 2018.

Referring to his signing, Saikawa said in court Wednesday, "At that time, it was not an official process, and I signed it without thinking too much because it was a draft."

He added that Ghosn had also expressed to the board how he was displeased with the disclosure requirements.

Prosecutors allege that Ghosn and Kelly had concealed the true remuneration to avoid potential criticism from stakeholders about receiving a large pay.

Kelly and Ghosn have denied the allegation, with Ghosn claiming his arrest was the result of a coup staged by Nissan officials.