Gwen Stefani has spent much of her career working with high-profile collaborators like Pharrell Williams. Other artists have helped Stefani create hits in her solo career, and she has often expressed gratitude for their efforts. She admitted it wasn’t always easy to work with them, though. Stefani said she felt threatened by her famous collaborators.

Gwen Stefani shared why she felt nervous around some of her collaborators

After finding success in No Doubt, Stefani struck out on her own. She released her debut album, Love, Angel, Music, Baby in 2004. While she had already proven herself as an artist, she was nervous about her solo career.

“She was nervous about it,” Jimmy Iovine, the head of her record label, told Rolling Stone. “It was her first time doing something without her band, and it was a big step. I said, ‘Let’s just experiment and see what happens.’”

She felt so nervous that she burst into tears before entering the studio.

“I cried before I went in the studio,” Stefani said. “I was just terrified.”

She collaborated with artists like Williams, Dr. Dre, and Andre 3000. Stefani admitted this terrified her.

“It was very threatening to let these people into my world,” she said. “Because that’s what I define myself as — a songwriter. The hardest part was letting someone even suggest an idea and then my ego being able to take it if it was good.”

She has gone on to collaborate with Williams many times over the years.