What singer made appearances during Keith Urban's Ripcord World Tour who also the winner of the  fourth season of "American Idol"?
Carrie Underwood Carrie Marie Underwood (born March 10, 1983) is an American singer, songwriter, and actress. She rose to fame as the winner of the fourth season of "American Idol" in 2005. Her debut album, "Some Hearts", was released in 2005. Bolstered by the huge crossover success of the singles "Jesus, Take the Wheel" and "Before He Cheats", it became the best-selling solo female debut album in country music history, the fastest-selling debut country album in Nielsen SoundScan history and the best-selling country album of the last 14 years. Underwood won three Grammy Awards for the album, including Best New Artist.
Kimberly Caldwell Kimberly Ann Caldwell (born February 25, 1982) is an American singer, actress and television hostess, from Katy, Texas who was the seventh place finalist on the second season of "American Idol". She used to work as an entertainment correspondent and hosted various shows on the TV Guide Network. She released her debut album "Without Regret" on April 19, 2011.