The 28-year-old singer's father is a preacher and is currently touring American churches with his wife Mary, reported Sun online.
"They ask how can I preach if I produce a girl who sang about kissing another girl? I was at a concert of Katy's where there were 20,000 fans. I'm watching this generation and they were going at it. It almost looked like church," Keith said.
"I stood there and wept and kept on weeping and weeping. They're loving and worshipping the wrong thing," he added.