Christina Aguilera surprises Chappell Roan fans with a "Coffee" duet in Los Angeles

Chappell Roan had a big surprise for her Los Angeles crowd. Midway through her show on Wednesday night she welcomed Christina Aguilera to the stage.

A shocker at the Shrine

Roan was headlining The Super Graphic Spectacular at the Shrine Auditorium. Fans in the packed venue lost it the moment Aguilera walked out.

The show was a benefit marking the first anniversary of Roan's Midwest Princess Project. Aguilera first sang her hit "Beautiful" on her own.

The two singers then teamed up on "Coffee," one of Roan's songs.

Roan's tribute

Before they started, Roan told the audience what Aguilera means to her. She credited the pop star with clearing a path for her and for every woman in pop who wants to do things her own way.

Using a few words that cannot be printed here, she said Aguilera had walked so she could run. She added that she felt grateful to share the stage with her and called her a legend.

A false start

The pair could barely stop grinning as the song began. Roan got the opening lines mixed up and had to start over.

Nobody seemed to mind. By the final notes the two voices were blending beautifully.

It was a night the crowd will be talking about for a long time.