The evangelical Christian parents of U.S. chart topper Katy Perry have lashed out against the lyrics of their daughter’s No. 1 hit single "I Kissed A Girl."

Her parents are outraged by the song’s provocative lyrics, which include “I kissed a girl and I liked it.”

Perry’s mother, Mary Hudson, says she is disappointed at the career path her daughter has decided to go down.

"I hate the song,” she said, according to the Daily Record. “It clearly promotes homosexuality and its message is shameful and disgusting. Katy knows how I feel. We are a very outspoken family."

"I can't even listen to that song," the mother added. "The first time I heard it I was in total shock. When it comes on the radio I bow my head and pray.”

The 23-year-old former gospel singer’s track continues to soar to the top of music charts around the world.

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"Katy is our daughter and we love her but we strongly disagree with how she is conducting herself at the moment," Mary Hudson said.

“We cannot cut her out of our lives as she is our child - but she knows we disagree strongly with what she is doing and the message she is promoting regarding homosexuality which the Bible clearly states is a sin.

"But the Bible also promotes understanding and forgiveness, which I keep reminding myself."

Hudson said, meanwhile, that Perry’s father has “had words” with her over her skimpy 50s-inspired outfits.

"Some are too revealing and her father has had words with her about it. Like any child she is going through a period of rebellion."

Perry, who has adopted her mother’s maiden name for the stage, used to sing for God in church and even released her own Christian pop album as Katy Hudson in 2001, which included the track “Faith Won’t Fail.” The record made it on to Christian Music Today’s best albums list that year.

But she was spotted by a music producer who invited her to LA, according to her mother, and "that’s when she started to change,” Mary Hudson said.

"I was worried she’d start doing drugs and drinking alcohol. I still am. I spoke to her only recently. She said, 'Oh Mum, I’m not going to turn into Amy Winehouse.’"