The collaboration is set for release this Friday, and has been accompanied by retro artwork that sees a lone tree set against a red print.
“Very excited about this one”, he wrote on Twitter.
CALVIN HARRIS // SAM SMITH // very excited about this one !!! @samsmithworld coming Friday.
Smith announced: “”Surprise!!!! I’m so excited for you all to hear this song.”
Although it marks Smith’s first collaboration with Harris, it’s his second foray into EDM after he previously joined forces with Disclosure on Latch.
Meanwhile, Sam Smith recently faced the wrath of Michael Jackson’s fans online after admitting he isn’t a fan of the late King of Pop.
The brave admission came as he holidayed with Adam Lambert, who recorded a video of the pair relaxing on a boat.
As the camera pans round to Smith, he admits: “I don’t like Michael Jackson, but this is a good song.”
The clip ends right after a few friends are heard to reply “wow’, admitting their surprise at the admission.