Eminem At The 2014 MTV Movie Awards
Eminem performs on stage at the 2014 MTV Movie Awards in Los Angeles, California April 13, 2014. Reuters/Lucy Nicholson

Eminem’s “Kings Never Die” collaborator Gwen Stefani has dished on the Detroit rapper and their collaboration song, which will be featured on the upcoming boxing film “Southpaw” starring Jake Gyllenhaal and Rachel McAdams. Eminem and Stefani co-wrote the song with the music group The New Royales.

“He's so incredible,” the No Doubt frontman said of Eminem during a recent interview with Entertainment Tonight at a BeautyCon tea party for the wide release of her Harajuku Lovers fragrance and Harajuku Lovers accessories. “He's a real artist. He's a real weirdo.”

Eminem and Stefani’s collaboration song “Kings Never Die” dropped on July 10. While she said she just made the collaboration happen, the former “The Voice” coach revealed the timing was not very good.

During the day of recording, Stefani said her voice happened to not be working but she “just prayed really hard and the engineer made it come to life.” After the recording, Eminem called her up to thank her but the timing was also not good because at the time, she was driving her children to soccer practice.

Aside from the collaboration song "Kings Never Die," Eminem also recorded a song titled "Phenomenal" for “Southpaw,” which is set to hit theatres in the United States on July 24 and on Aug. 20 in Australia. Directed by Antoine Fuqua and written by Kurt Sutter, the boxing film also stars Forest Whitaker, Naomie Harris, Rita Ora, Miguel Gomez, Clare Foley, Victor Ortiz, Grace Marie Williams, Skylan Brooks, Oona Laurence and Eminem’s protégé 50 Cent, among others.

Also during the BeautyCon event for her Harajuku Lovers fragrance and Harajuku Lovers accessories launch, Stefani talked to People about her hair colour and signature lipstick. She was laughing when she told the publication that she has thought about going brunette.

Stefani said going brunette will make her feel sad. She said she will add in a little black to her hair to change it up, but she just loves being blonde. In terms of her signature lipstick, she revealed that she lost count of how many she has in her makeup kit. Admitting that she has so many red lipstick shades, Stefani said she really does probably have five that she somewhat goes in and out of adding that her favourite is an Urban Decay colour.

For questions/comments regarding the article, you may email the writer at c.altatis@ibtimes.com.au.