The track premiered on The Chris Moyles Show on BBC Radio 1 on 28 August 2012 and was later released as the fifth single from the album on 12 October 2012.

In the video, Welch works as a singer at a bar or club, pouring the pain and frustration of her unfulfilled life and abusive relationship into every revealing and explosive performance.

On 30 July 2012, Calvin Harris stated via his Twitter account that his third studio album 18 Months would be released at the end of October 2012.

"[6] "Sweet Nothing" first premiered on The Chris Moyles Show on BBC Radio 1 on 28 August 2012,[7] and was released as the fifth single from the album on 14 October 2012.

It is an electronic dance music song, following the familiar pattern of taking love-strung vocals and layering them over a bouncy, ever-building beat.

After its premiere on the radio, Robbie Daw of Idolator stated, "If there was any doubt as to whether Harris is the current king of frothy, radio-friendly dance pop on both sides of the Atlantic, one need only listen to this energetic jam.

UK called it "a pop pairing made in heaven", writing, "The club friendly track features Calvin's latest knob twiddling genius that never seems to get old despite debuting in last year's monster anthem 'We Found Love'.

"[11] Billboard was very positive, writing, "The bass glimmers underneath Welch's operatic chants, as the singer, freed momentarily from her well-oiled Machine, gets to re-imagine her career as a dance goddess.

"[13] Emily Mackay of NME agreed, stating that "the highest point apart is Florence's dance-diva turn on the p-p-p-p-powing power-house of 'Sweet Nothing'.

"[14] Adam Pollock of Filter magazine opined, "A thrilling guest vocal by Florence Welch adds an excitingly dark vibe to the album, which for the most part stays in booty-shaking mode.

"[15] Bill Lamb of About.com rated the song three-and-a-half out of five stars, calling it "satisfying as a pop radio treat, but it leaves fans hoping for something just a little deeper and more memorable.

"[10] He criticised the song for "failing to go much further beyond the arresting opening," however he wrote that "Calvin Harris' disco-inflected pop remains irresistible.

"[10] Tim Sendra of AllMusic was mixed, writing that "Florence Welch's desperate wail pushes it over the top.

"[16] Melissa Maerz of Entertainment Weekly agreed, writing that "Welch's banshee wail gets buried under the laser-gun peals of 'Sweet Nothing'.

"[18] In the UK midweeks charts, "Sweet Nothing" was ahead of Swedish House Mafia, knocking their track "Don't You Worry Child" into second place.

[citation needed] The song was a commercial success in Australia, debuting at number 2 on the ARIA Charts week of 28 October 2012.

[23] "Sweet Nothing" was certified 2× Platinum by the Australian Recording Industry Association (ARIA), denoting shipments of 140,000 copies.

[33] On 23 August, Harris announced via Facebook that he was filming the music video for "Sweet Nothing" with Florence and the Machine.

The exterior shots were filmed close to Stepney Methodist Church Bus Stop on Commercial Road, Limehouse, London.

[36] The video stars Harris and Welch, as well as English actors Leo Gregory[37] and Kianoush Joseph.

Harris watches as Welch takes off her suit and tie and frees her hair to reveal herself as the girlfriend being abused by Gregory.