"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 mum 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.

When they finished belting the worship song, judge Luke Bryan requested the pair sing "Oh Happy Day," another gospel song made popular by the movie "Sister Act 2."

McCain and Perry than proudly sang about Jesus washing their sins away together. The chart-topping singer got so inspired that she stood up to clap and dance to the song.

"Oh happy day, when Jesus washed, He washed my sins away," she worshiped with McCain. "He taught me how to fight and pray and He rejoices in every way."

The young man received a collective "yes" from all three judges and advanced with the golden ticket to Hollywood.

"I knew I'd do all right, but I didn't think I'd come out there knowing I sang with Katy Perry," McCain told ABC News Channel 9 after the audition.

Perry was raised by Christian parents who are traveling Pentecostal ministers. She started singing Christian music but after not making it in that industry she turned to pop music. The artist has said that she no longer identifies as a Christian, but some speculate that her social media posts and comments during the singing competition might indicate that things are changing.