Carrie Underwood was taken aback by an American Idol contestant - not for the first time this series - and found herself singing along to her own anthem, "Waiting All Day For Sunday Night." The 2005 American Idol winner is now a judge on the hit show and was treated to a rendition of her famous song,

Carrie Underwood was surprised by an American Idol contestant and left singing along to her own anthem, "Waiting All Day For Sunday Night." The 2005 winner of American Idol was treated to a rendition of her famous song,

Carrie Underwood showed off her skills during an American Idol clip, but some fans disapproved of her performing with a contestant.