Following Kelly Clarkson's performance last week and Lee DeWyze earlier this season on "American Idol," the former winner train continued last night with David Cook.
The Season Seven winner returned to the show that made him famous on Thursday to debut his new single, "The Last Goodbye."
Cook also announced he'll be taking part in the Race for Hope in DC, a walk/run whose profits go to ABC Squared -- a brain cancer research organization. David's brother passed away from the disease in 2009.
For more information on ABC Squared, check out the organization's website.