Ariana Grande & Chris Martin Duet on 'Just a Little Bit of Your Heart' at Global Citizen Festival: Watch

Chris Martin; Ariana Grande
Kevin Mazur/Getty Images for Global Citizen

Chris Martin of Coldplay performs with Ariana Grande onstage during 2015 Global Citizen Festival to end extreme poverty by 2030 in Central Park on September 26, 2015 in New York City.

Ariana Grande and Coldplay’s Chris Martin turned the touching My Everything ballad “Just a Little Bit of Your Heart” into a duet at the 2015 Global Citizen Festival in New York City on Saturday, Sept. 26.

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“It was an honor to say the least,” Grande gushed on Twitter, before heading down to Brooklyn for the first of two of her own tour dates at the Barclays Center.

Coldplay, meanwhile, tweeted about a piano that broke at the last minute, just before taking the stage -- and that the band had only rehearsed the performance on piano with Grande.

“Just a Little Bit of Your Heart,” which was co-written by One Direction’s Harry Styles, is originally a piano-driven album track, but for Saturday night’s festival surprise, Grande sang the song alongside an acoustic guitar-strumming Martin.

Grande has been full of musical treats for her fans over the past week. On Friday, Sept. 25, she revealed "E Più Ti Penso,” a duet with Andrea Bocelli.

Check out Grande and Martin’s “Just a Little Bit of Your Heart” duet below.