The judge clearly found it difficult to talk as he fought back tears while praising the group for their moving performance.
When asked by hosts Ant and Dec what he thought of their song choice, the comedian was close to tears as he told them: "I just feel unbelievably sad after what I just saw and what I just heard.
"It just hits you, I just feel so emotional, but what I think is incredible is that you're turning all of these sad stories into something full of hope and you're reaching out and you're saying…
"You're asking the public to help you and the song, it's hard to separate everything out but you sang the song so beautifully."
The Missing People Choir left the judges struggling to speak
He fought back tears while praising the group for their moving performance
I just feel unbelievably sad after what I just saw
He went on to add: "I'm sure everybody at home, like us, is incredibly moved by that."
Fellow judge Alesha Dixon was also close to tears as she praised the choir for using the Britain's Got Talent "responsibly" to help find those who are missing.
"You've made such an impact on the country, so many people are rooting for you," she told them. "I want you guys to be in that final.
"This message is so important. I'm so proud to be a part of this show because this is how you use the platform responsibly."
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Alesha also fought back tears as she praised the choir's performance
Alesha said she believes the Missing People Choir could go on to win the show
Alesha previously told Express.co.uk that she believed the choir could go on to win this year's competition.
"I think everyone watching had empathy for them and compassion for them and respected them and admired them," she commented.
"I think the nation's behind them 100 per cent so they could win. It's all down to that performance on the night."