Gwen Stefani may be a true believer in the saying "ask and you shall receive."

The No Doubt songstress recently teamed up with Eminem for their new hard-hitting single "Kings Never Die" off the "Southpaw" soundtrack. Working with Em was a no-brainer for Gwen, even if she does consider the rapper a bit of a "weirdo."

"I've been asking for so long to do something with him," Gwen told "Entertainment Tonight." "I think he's so incredible, a real artist, he's a real weirdo, we all know that."

Gwen got the unexpected call to collaborate with the "Phenomenal" rapper and literally had to drop everything to get into the studio, where she encountered an unexpected problem.

"I just finally got the call and it was one of those days where they are like, 'Can you come do this?' And I was like, 'Really? Really?' And they are like, 'It has to be done today.' And I was like, 'OK!'" Gwen explained. "And I went down there and my voice happened to not be working that day, so I was like, 'Oh, perfect, the one time I get asked to be on an Eminem song.' I just prayed really hard and the engineer just made it come to life."

Well, we didn't hear anything but Gwen's flawless vocals, and neither did Eminem, who personally called her, while driving with her three kids, to thank her.

"I'm driving in the minivan with all my kids in the car and somebody calls and I'm like, 'Hello?' And it's him, it's the guy, it's him," She said. "And he's like, 'Hey, I just want to say thanks for doing this,' and I'm like, 'you can't call me right now, all my kids are in the car! Don't say any bad words!' I was literally going to soccer practice, but I was like, 'I'm gonna make your song so cool!'"

Em curated and executive produced the soundtrack for the boxing drama flick, “Southpaw,” which also features The Weeknd, Action Bronson, and more.