The star was performing at Manchester Arena as part of her 'A Million Lights' tour when she asked the crowd to wish her new partner a happy birthday.
Cole, her dancers and the audience sang Tre 'Happy Birthday to You' before he was handed a cake and blew out the candles.
The backing dancer waved to the audience and ran over to kiss Cole before he left the stage to huge cheers from the crowd.
Cole's first solo headline tour of the UK will conclude at the Metro Radio Arena in Newcastle on October 17, before the star rejoins Girls Aloud for a special announcement on Friday (October 19).
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