"This has always been home to us and I felt this was the perfect place to ask a simple question," Young, 31, said.
"We have conquered Broadway together, we have created new music together, we have an amazing group of people around us and, with the help of David Webb jewelry, I have a way to make this fun last forever. You ready?" Young said. "I love you to death, you're my best friend. I want to make this last forever and I would do anything in my power to have the most imaginable and amazing life together, if you will have me. Diana Nicole DeGarmo, will you marry me?"
DeGarmo, 24, said yes and the couple kissed as the audience cheered, E! News reported.
"I'm so speechless right now!" she said. "And my makeup's runnin' right now."
DeGarmo competed during the third season of "American Idol" and Young was a Season 5 contestant. They co-starred in the Broadway musical "Hair."