Katy Perry has taken aim at an ex before but never with so much passion. In her first U.S. performance since her split from Russell Brand, the 27-year-old debuted a new song called "Part of Me" at Sunday night's Grammy Awards.

Dressed in a skintight plastic jumpsuit, Perry took the stage belting out some less-than-subtle lyrics: "You chewed me up and spit me out/Like I was poison in your mouth/You took my light, you drained me down/That was then and this is now."

Perry made sure that everyone knew she was taking aim at Brand with the lyric:

"Look at me/ I'm sparkling/ You will never put me out again/ So you can keep the diamond ring/ It don't mean nothing anyway."

Brand, 36, and Perry finalized the the details of their divorce last week, in what was one of the quickest and most amicable in Hollywood history. The couple didn't sign a prenup and Brand reportedly refused to take the $20 million he would have been entitled to under California law -- half of what Perry earned during the 14 months they were married.

Although Perry signed her divorce papers with a smiley face, her new song speaks volumes as to how much Brand hurt her.

Perry has been known to get over breakups using her music. Her debut song, "Ur So Gay," took aim at a string of boyfriends who wore "guyliner" and borrowed her jeans, while "Circle the Drain" called out Gym Class Heroes frontman Travie McCoy, and his addiction to prescription drugs, which contributed to their breakup.