(TMZ) - Justin Bieber was rushed to a hospital in London moments ago ... after collapsing backstage during a concert... TMZ has learned.
A source close to Justin says the singer felt woozy during the show at the O2 Arena ... and with 4 songs to go, he stumbled backstage where he collapsed.
Bieber was pulled into a private room where he was treated with oxygen from emergency personnel.
Sources say Bieber was advised to go to the hospital... but declined... insisting that he "had to finish the show for his fans."
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