Cavanagh, who had frequently found herself in the show's danger zone of being voted off, wowed the judges on Wednesday with her soaring energy and Tina Turner-like dance moves in her take on "River Deep Mountain High."

Contestants sang hits from the 1960s, followed by songs by British artists on Wednesday, and "Idol" got a visit from one it most famous past winners, country songstress Carrie Underwood on Thursday elimination episode.

Now a top country star, Underwood performed the title track from her album "Blown Away," which was released earlier this week. Coldplay sang their song "Paradise," and came back later in the show for an encore performance.

Four contestants remain on "Idol" heading toward the show's finale later this month.

"Idol", which first aired in on Fox in 2002, has launched the careers Kelly Clarkson, Adam Lambert and Jennifer Husdon, among others. Now in its 11th season, the show continues to be the most watched reality TV show in America, though it has received stiff competition from "The Voice" this year.

Audiences vote for their favorite performers by phone and text message each week as contestants are challenged by a variety of musical styles. The winning contestant receives a recording contract.