An American music producer gave evidence in a New Zealand courtroom on Tuesday (May 2), claiming the track he co-wrote with rapper Eminem has been unlawfully used for political advertising.

New Zealand’s National Party used a track entitled “Eminem Esque” in a 2014 election campaign advert and Eminem’s music publishers are suing them for copyright infringement, local media reported.

Bass played the riff to Lose Yourself to a Wellington court on Tuesday, saying he believed the campaign had infringed copyright.

‘Lose Yourself’ was featured in the 2002 movie 8 Mile, where Eminem played the lead role of a struggling rapper, and the track won the Academy Award in 2003 for Best Original Song.