Inspired by Lewis' break-up with childhood sweetheart Lou Al-Chamaa, "Trouble" is a mid-tempo R&B and trip hop ballad, with a piano and strings-driven melody.

It was written by a British writing collective consisting of Lewis, Donald Glover, Hugo Chegwin, Harry Craze, Shahid Khan, James Murray, Mustafa Omer, Emeli Sandé and Fraser T Smith.

Music critics noted that the urban production marked a new direction for Lewis, particularly by featuring Gambino during the song's middle eight breakdown with a poetic rap verse.

"Trouble" was also influenced by British trip hop duo Massive Attack, who Lewis cited as a musical inspiration.

As part of promotion of the song, fans were given chance to produce their own remix of "Trouble" which was released alongside the single on Lewis' official music store.

An accompanying music video was filmed on 22 August in Los Angeles, with Teen Wolf actor Colton Haynes cast as Lewis' love interest.

"Trouble" was promoted with performances on the ninth series of The X Factor (UK), on 7 October 2012, later on Alan Carr: Chatty Man and also during a set at London nightclub, G-A-Y.

Sony Music made "Trouble" a global priority, making it supersede "Collide" as the album's lead single and focussing on promoting the song in the UK first before a worldwide release.

[20] "Trouble" was played at a press premiere for Tracey Hart from Music Week magazine, along with new songs "Come Alive" and "Un Love Me".

[24] "Trouble" is a mid-tempo R&B and trip hop song written by Lewis and collective of British songwriters, including Hugo Chegwin, Harry Craze, Shahid Khan, James Murray, Mustafa Omer, Emeli Sandé and Fraser T Smith.

[29] In a press release, Lewis explained the meaning behind "Trouble": "it tells the story of love going bad and becoming destructive, aspects of which we can all relate to.

"[22][30] During an interview with Digital Spy, Lewis further explained that she was inspired and influenced by British trip-hop pioneers Massive Attack.

[25][31] "Trouble" received mainly positive reviews from critics, who praised Childish Gambino's featured rap, the musical production and Lewis's emotive vocals.

A reviewer from Pop Justice said that the site had twice heard "Trouble"; the first time was just before "Collide" was released in September 2011, while a second finished version was played for them on 16 August 2012.

"[22] The reviewer commented, "['Trouble' has] a convincing, compelling and dramatic vocal performance which works brilliantly against the song's opulent but bleak mid-tempo production", adding that although Childish Gambino's "rap in the middle eight sounds great", it almost "slightly dilutes Leona's big comeback".

[32] Commenting on the song as a whole, Corner said "Trouble" was a powerful comeback, "It's big, it's emotional and it's what we've come to expect from the Hackney belle – but we wouldn't want it any other way.

"[32] Lewis Corner from Digital Spy also picked up on the change of direction and commented that people would be "shocked," but then added that "when "it results in an emotive anthem like this, we hope she unleashes it more often.

[31] In a later review, Corner said that "Trouble" was built around "echoing beats and heart-tugging piano riff," which when combined with "her unmistakable falsetto" was as dramatic as a scene from the film The Hunger Games.

[28] Elena Gorgon from Softpedia echoed earlier sentiments, concluding that the song "was powerful, it's heartfelt and it confirms Leona as one of the most remarkable vocalists of the day.

[34] Whilst the majority of reviews praised Gambino's appearance on the song,[22][31][32] Cheeseman described the collaboration as "a saviour" but that it did nothing for Lewis' "credibility".

[25] Her review was subtitled "Leona Lewis Tries to Convince Us She's 'Trouble' — We're not buyin' what she's sellin'" and concluded that if the best that Glassheart could preview after all the delays was "Trouble", "it won't be worth the wait.

"[25] NME's Jeremy Allen agreed, praising the production on "Trouble" as "slick" but stating that from Lewis it does not come across with conviction nor is it believable.

[47] According to MSN's Felicity Thistlewaithe, Haynes was chosen due to his physical resemblance to Lewis' ex-boyfriend Lou Al-Chamaa, who is thought to be the inspiration for the song.

[49] Described by Capital FM as "Lewis enduring an awkward break-up" interpolated with "time[s] when the couple were happy and in love," the music video for "Trouble" uses the solo version of the song, which excludes Childish Gambino's rap verse.

[51] During the second airing of the chorus, more images of happy scenes between the couple are spliced with Lewis waking up in bed to find Haynes has slept on the sofa.

[51] Anna Lewis from Heatworld.com praised the music video and said that fans who "like listening to good tunes and looking at hot guys" would be impressed.

[60] Matty Graham won the competition, and his remix of "Trouble" was released alongside the original version as part of a Digital EP available exclusively to MyPlayDirect.com, Lewis' official music store.

[64] A tour of local radio stations in the UK began on 17 September, lasting for four days and visiting six cities to promote both "Trouble" and Glassheart.

[21] Music Week magazine was first to reveal that Lewis would be performing over the first live shows on 7 October, directly preceding the song's release.

[66][67] Internationally, Lewis took to the stage for second season finale of The Voice of Germany, where she performed "Trouble" as a duet with finalist Michael Lane.