The Tony Award-winning actress will sing "Let It Go," which is nominated for Best Original Song up against tunes from Despicable Me 2, Mandela: Long Walk to Freedom and Her. Frozen is also up for best animated feature.
"It's really happening. I'm singing on the Oscars! Surreal," Menzel tweeted Tuesday. "Thank u frozen family and Oscar producers for this incredible opportunity."
The 86th Academy Awards, hosted by Ellen DeGeneres, airs Sunday, March 2 at 8:30 p.m. ET/ 5:30 p.m. PT on ABC.