Gwen Stefani "kept forgetting lyrics" to No Doubt songs before a TV performance so asked fans for help.

The singer and her band appeared on US show Good Morning America last Friday to perform some of their greatest hits as well as new material.

But the 42-year-old star seemingly had trouble remembering the words to some of the group's material during the sound check and had to ask the audience of keen fans to help her out.

"Gwen kept forgetting lyrics to the band's older songs Underneath It All and It's My Life," a source told The New York Post. "She kept asking the early-rising crowd for help, and they joined in."

The iconic frontwoman later delivered what has been described as a "killer performance" but was extremely grateful to her loyal fans.

She repeatedly thanked the crowd who had arrived in the early hours of Friday to watch the 7am rehearsal.

"I bleeping love you! I can't believe you're here so early," she told the audience.

No Doubt recently performed together for the first time in 11 years after a hiatus and are currently promoting their upcoming new album Push and Shove, set to be released in September.