American Idol

Idols' Dream Duets

See which superstar vocalists Syesha Mercado, David Archuleta and the rest of the top 10 would love to sing with

Jason Castro & Gwen Stefani

"It would be really cool to do something with Gwen Stefani," says Castro. "I have been a fan of her music since No Doubt and I just love her style. It would be really cool to partner with her."