Foo Fighters frontman Dave Grohl said listening to singer Katy Perry's latest album is a "real test" in proving you would do just about anything for your children, according to NME.

Grohl mentioned his thoughts about the singer's music when asked about what his kids are listening to.

"The worst thing [my children] impose on me is Katy Perry's album," Grohl said in an interview with Red Bulletin. "Her music is a real test in terms of loyalty towards your kids."

Answering if Perry's music doesn't make him happy, Grohl was firm: "No, not at all." Speaking of another pop star Lorde, however, Grohl had nothing but good words.

"Her song 'Royals' is its own little revolution in the sea of bullshit," the former Nirvana drummer said.

He then went on to speak about how he thinks pop music these days lack substance.

"Pop music in America right now is so superficial. It's fun to listen to...but there's no substance at all," Grohl explained. "It's devoid of any meaning. I'm not just saying that as a 45-year-old rock musician, I'm saying that as a human being."

He continued, "When I heard 'Royals' in the middle of all these other songs, I thought, 'Thank God! Someone's singing something that actually has a little bit of something."

Grohl had previously spoken about his admiration for Lorde in an interview with Rolling Stone. He also mentioned why he chose the New Zealand-born singer to perform for Nirvana's induction to the Rock and Roll Hall of Fame last April.

"There's something about her that presented or resembled the Nirvana aesthetic. She has an incredible future ahead of her as a writer, performer and vocalist," he said.

Grohl is currently preparing for the Foo Fighters' 2015 tour. They have recently announced the massive North American leg of the "Sonic Highways" series of shows, which will kick off on July 4, 2015.