The star performed “Just a Little Bit of Your Heart,” a song he wrote for Ariana, to honor the victims of her May 2017 bombing attack.
“She sang it a few times, and now we’re going to do our version of it for you — and if you can find some way to join in please do so. I stand with you, Manchester,” Harry said on stage.
Watch the emotional performance below.
More Harry: Check out the best photos from his tour so far.