Entertainment Tonight.

"American Idol" winner David Cook took the concert stage Friday night in Ohio, and he alluded several times to his sadness over the loss of his older brother Adam, who passed away from cancer on May 2.

David, brandishing a guitar with his brother's initials on it, sang a little bit of the Eagles' "Hotel California" and told the crowd, "Adam would be proud," says People.com.

Also during the concert, he stopped playing a song and told the audience, "It's gonna be tough for me," adding, "Hold on. I'm sorry. Do you mind if I sing a different song?"

The Web site says that although the 26-year-old star appeared to grapple with his emotions, he at times seemed upbeat, referring to himself as "Old Dave."