It was the first time Menzel had performed the song live on television, and her first time singing at the Oscars.
"If I wasn't nervous, something would be a little off," the Tony Award winner said before the show.
Frozen won Best Animated Feature earlier in the night, and "Let It Go," which was specially written for Menzel by Kristen Anderson-Lopez and Robert Lopez, also won Best Original Song against "Happy" from Despicable Me 2, "Ordinary Love" from Mandela: Long Walk to Freedom and "The Moon Song" from Her.
Menzel's appearance wasn't without its glitches: John Travolta, who introduced Menzel's performance, inadvertently mispronounced her name, leading host Ellen DeGeneres to later say the singer's name correctly.
The snafu also quickly spurred a parody Twitter account called "Adele Dazim."
Thanks for the introduction, John! #oscars— Adele Dazim (@AdeleDazim) March 3, 2014
Menzel, 42, who posted a pic of herself warming up in the bathroom backstage before the final run-through, admitted she had a plan to beat the jitters: pretend she was singing the song to her son, Walker, 4, at home.
The voice of Frozen's Queen Elsa, who rocked the red carpet in a hunter green Vera Wang dress, Tweeted a pic of the pre-show crush along with the caption, "This is surreal."
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