Christina admitted she had a bit of stage fright before she sang at The Social Network star's third annual Justin Timberlake & Friends concert that benefits Shriners Hospitals for Children.
The 29-year-old, who recently filed for divorce from Jordan Bratman, told Etonline.com: 'I haven't performed in a little while.
'I've been working on the movie Burlesque so it's nice to get back on stage again but it's a little nerve wracking.'
Timberlake, who hosted the event which took place last Saturday night in Las Vegas, added: 'Christina I've known since I was ten, I'm always excited to hear her sing - it's pretty breathtaking.'