'American Idol' pick top 20: Katy Perry brought to tears by contestant Christian Guardino's John Lennon cover

'American Idol' pick top 20: Katy Perry brought to tears by contestant Christian Guardino's John Lennon cover https://ift.tt/7ctjFve

"American Idol" contestant Christian Guardino's moving rendition of a John Lennon classic brought judge Katy Perry to tears Sunday night.