Ariana Grande, Cynthia Erivo Perform 'I'm Every Woman' Live on 'Today'

Ariana Grande and Cynthia Erivo are proving they're perfectly in-sync ... busting out into song during their recent appearance on "TODAY."

Check it out ... the stars of the upcoming "Wicked" film sit down with Savannah Guthrie and Hoda Kotb to discuss their bond after making the musical movie -- and give a taste of their pitch-perfect sound together.

When asked by Hoda if there's any song they can't help but sing when around one another, the on-screen besties confess "I'm Every Woman" by Chaka Khan is a favorite ... jumping into a live rendition of the song.

Cynthia adds before the impromptu performance ... "We haven't done it for anyone yet, but it was on and we were singing together and it sounded nice."

We're sure "TODAY" audiences are in agreement after getting the little snippet on Wednesday morning's show.

Cynthia and Ariana have had quite a bit of practice singing live together, given the fact they sang all of their tunes live on the "Wicked" set.

The big-screen adaptation of the Broadway hit is set to be a Blockbuster next week, with the stars of the film embarking on a global press tour to promote the film.

Ariana is certainly feeling "Popular" ahead of the flick's November 22 release ... we caught her out in NYC Tuesday, where she was mobbed by fans clamoring for autographs.