The producer, who teamed up with Rihanna for the club banger, has backed up Leona’s recent admission that she had actually recorded the popular track first, but the Bajan songstress snapped it up as soon as she heard it.
Speaking to Kiss FM, Calvin refuses to say which version is his favourite, but does reveal that Leona’s rendition is completely different to Rihanna’s dance take.
“Erm, they’re very different because [Leona] sings it dead softly, you know, how Leona sings,” Calvin said.
“It’s more like an X Factor ballad.”
While Leona recently said no one will ever hear her version, Calvin says he has the power to surprise fans by releasing it one day.
“The only people that have got it are me and Leona Lewis,” Calvin added.
Meanwhile, the DJ has been forced to play down his Twitter spat with Lady Gaga, who blasted him for claiming he turned down her offer of a collaboration.
“You got to pick people whose songs or voice that you like,” Calvin told BBC Breakfast.
“And in that stage, it was before she was very big. But they sent me some songs and I didn’t really like the songs.”
‘Born This Way’ singer Lady Gaga hit back on Twitter: “Seems to be trendy lately to talk shit about “lady gaga” when your albums/singles drop. Y’all should live off your own hustle. #Ido.”
“Music is mortal if it has no integrity behind it. I’m interested in making the immortal kind,” she continued.
“never even emailed you @calvinharris I guess it’s hard to believe I write + produce my music. cuz I’m a woman I don’t know about EDM right?”
Calvin replied: “@ladygaga no your label emailed me. I always make sure I say Im a fan when asked about it, I apologise if I offended u, wasn’t the intention.”
Do you want to hear Leona’s version of ‘We Found Love’…