Jessica Simpson (AP file photo)

Jessica Simpson was left red-faced at a concert in California on Saturday when she messed up the opening lyrics to two of her songs.

The singer played her final gig as the support act on Rascal Flatts' Bob Your Head Tour in Irvine at the weekend, but her last show was dogged by mishaps as she forgot the lines to Remember That and Still Don't Stop Me.

After getting the lyrics mixed up for Remember That, a track about being in an abusive relationship, she told the crowd, "Oops! I said whiskey too early! I messed up!

"I'm so embarrassed! But I'm starting over again because I really want you guys to hear the lyrics the right way."

And she nervously giggled when she got the lines wrong during Still Don't Stop Me, before saying: "I messed up again! I do this all the time!"