Killers frontman Brandon Flowers brought the band's producer, Stuart Price, on stage as a special guest at his solo show in London on Tuesday.
Flowers explained he had first became aware of the Grammy-winning producer when he remixed Mr Brightside under his pseudonym Jacques Le Cont in 2005.
"I thought, 'who is this guy? Is he from France?'" Flowers told the audience at Brixton Academy.
When the duo finally met over dinner in London, Flowers asked Price to record a demo of a new song "as a test".
The track later became the top 10 single Human, and Price has since helmed The Killer's Day And Age album and Flowers' solo debut, Flamingo.
On stage, the producer - who has also worked with New Order and Madonna - strapped on a guitar and played an encore of three songs: Human, Only The Young, and his synth-powered remix of Mr Brightside.
Speaking to 6 Music before the show, Flowers said his solo project was "winding down" as he prepared to become a father for the third time in the New Year.
But he told 6 Music's Mark Savage he was still writing new material and he is over the moon with the response to the album:
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