"I don't understand why you want to know," said Aiken after Sawyer asked him if he really was gay. "I don't understand why it's any of your business."
"At some point, (the question) becomes just really rude, you know?" said the singer in the interview that aired Thursday on ABC's "Good Morning America," the New York Post's Page Six reported.
Aiken's sexuality has been gossiped about since he came in second place on "American Idol" and became an overnight star in 2003.
This year has been especially rough for the singer after a former Green Beret alleged that he hooked up with Aiken through a gay Internet site.
"I just don't understand why people care, to be honest with you. I'm not spending my time with this anymore," said Aiken, adding, "This is a waste of my time."