Jessica Simpson was left red-faced and seething after an excited fan mistook her for arch enemy Carrie Underwood during a June 11th lunch date at Dos Caminos in the SoHo section of New York City.

“She wasn’t pleased that the girl had no clue who she was….She said she was her number-one fan from back in the Idol days,” a celebrity snitch spilled to OK! “Jessica smiled politely and didn’t correct her, and she started to laugh when the girl asked how she was doing since her devastating split from Chace [Crawford].”