Katy Perry and Luke Bryan were left in tears after one American Idol hopeful - Cam Amen - left it all over the stage during his audition.In a clip from this Sunday March 26's episode, Cam sings his version of Leonard Cohen's classic 'Hallelujah', and also revealed he grew up in foster care before he raised his brother and sister when he turned 18. Katy was visibly emotional as Luke had tears in his eyes, and the pair along with Lionel Richie gave Cam a standing ovation and hugs after the performance.