The 26-year-old "Hills" singer is now sober following stints of heavy partying and drug-taking at the beginning of his career, and he said he used to go on stage drunk to help him get through the show because he was so worried about singing in front of thousands of people, reported Contactmusic.
"You have to fight the nerves, man... You're singing to people, it's an emotional thing," he said.
"It's nerve-racking... You're literally putting yourself out to hundreds and thousands of people. You have to fight that. That's something I had to do and once I did, I feel like people are more nervous to see me than I am to see them. I love performing.