Heartbroken Katy Perry has warned fans her fun-loving pop music is about to get "dark" as she channels her emotions from her split from comedian Russell Brand into her new work.

The I Kissed A Girl hitmaker is known for her light-hearted catchy tunes, but she admits her failed marriage has inspired her to vent about the break-up through her lyrics.

In a candid chat with America's Interview magazine, for which she is photographed as a sexy burlesque dancer, Perry says, "My music is about get real f**king dark. I'll be shoe-gazing. You'll never see my face because my hair is in my face."

Perry recently performed her new song Part of Me at the Grammy Awards and was said to have changed the line "You can keep the dog/I never liked him anyway" to "You can keep the diamond ring/it don't mean nothing anyway" to reflect her newly-single status.

The star insists the single was written in 2010, before her marriage, but it has taken on a whole new meaning now she's no longer Mrs. Brand.

She says, "I wrote Part of Me two years ago and I always knew that Part of Me was a special song.

"It feels like my life plays out with these songs. I feel like I'm in some kind of weird Truman Show (Jim Carrey film), where I'm like, 'Why is this single appropriate now and it wouldn't have been appropriate then?' It's just so crazy.

"I guess the universe is kind of... we're kind of like, dancing together in some weird way... I think it's really important for me to write songs that are still honest and relatable because that's what everyone else is going through."

Brand ended the couple's 14-month marriage when he filed for divorce on 30 December.