"If I wasn't nervous, something would be a little off," the veteran Broadway songstress, who voices a main role in "Frozen," told AP Live on the Oscar red carpet.
She said she had a plan for calming her nerves: Pretending she was singing the song to her young son at home.
The song has gone viral, with countless young girls making their own versions and posting them on YouTube.
"It's about liberating your soul and accepting yourself for who you are," Menzel said.
- Jocelyn Noveck - Twitter http://twitter.com/JocelynNoveckAP