The "American Idol" alum who simulated oral sex and shared a same-sex lip lock on stage said he used to be a hefty high school kid who would feed off his audiences' reactions to his performance.
"When I was in high school I was 250 pounds and that creates some stuff ... some body image stuff, some confidence issues, and I got a lot of my confidences from validation I got as a performer," he told the radio station.
Lambert stopped short of apologizing for his kinky stage act but said he "did get carried away." The performance drew 1,500 complaints and caused him to be booted from G-rated ABC morning show "Good Morning America."
The 27-year-old singer came out as gay in an interview with Rolling Stone earlier this year. He'll be a guest on "Ellen" on Tuesday.