"American Idol" judge Katy Perry tapped into her Christian singing roots on the competition Sunday, joining high school senior Drake McCain as he praised God with two classic gospel numbers.

McCain, the eldest of eight children, has helped his single mom raise his brothers and sister his whole life and said he joined the competition to inspire his siblings.

ABC's new season of "American Idol" premiered this month and unlike most of the other young singers who auditioned with pop songs, on episode two, McCain chose to use his performance to worship God by singing the popular gospel hymn "His Eye is on the Sparrow," taken from the Bible verse Matthew 6:26.

As he sang, judge Katy Perry, who grew up in church, joined in. McCain and the pop star harmonized in a powerful rendition of the song.

"I sing because I am free, His eye is on the sparrow and I know He watches me," they sang. 

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