Rita Ora Emotional While Playing Liam Payne Song at Concert, Leaves Stage

Rita Ora 's clearly feeling the loss of Liam Payne ... getting so emotional at her show last night, she couldn't even sing -- and straight-up walked off the stage at one point.

The singer-songwriter performed in Japan just hours after news of Liam's tragic death in Argentina broke ... and, she played her hit song "For You" -- the track recorded for "Fifty Shades Freed," which features Liam.

While the song plays, Rita walks around the stage looking at the audience and waving her hands in the air. She's letting her fans drive this one -- allowing them to lead the music.

At one point, Rita sits down onstage -- saying it's too difficult for her to even sing -- and asks the audience to raise their voices to compensate for her own.

A picture of Rita and Liam -- which RO later posted to X with a heartfelt caption -- appeared on the screen behind her ... showing the two cuddled up working on music together.

Rita leaves the stage before the video cuts off. Unclear if she came back out, or if this was the final song ... but, either way, it's clear Rita's reeling from Liam's death.

REMEMBERING LIAM PAYNE

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As we told you ... Liam fell to his death at a Buenos Aires hotel Wednesday afternoon after a 911 call from a hotel employee who said he was "overwhelmed by drugs and alcohol" -- and staff were worried because they hadn't had access to the room for several days.

Rita is one of many celebs remembering Liam . Everyone from Juicy J to Flavor Flav to Paris Hilton has posted their condolences. He will certainly be missed.