"Hangover" is a song by English singer-songwriter Taio Cruz from his third studio album, TY.O. Released on October 4, 2011 in Germany, and March 4, 2012 in the United Kingdom, the song serves as the album's international lead single, and follows Troublemaker as the album's second British single. American rapper Flo Rida contributes guest vocals. It was written by Taio Cruz and co-written and produced by Dr. Luke and Cirkut.

In an interview with Billboard, Taio said that fans can expect more uptempo dance tracks on his forthcoming album. Talking to Billboard, Cruz explained: "The new album will be out by the end of the year; it will be out before Christmas. The new single will be out very, very soon as well." He also said "It's definitely going to be more of the uptempo, fun, energetic vibe that you've heard on 'Break Your Heart', 'Higher' and 'Dynamite'." Speaking about potential collaborations, Cruz revealed: "There are a few guests—David Guetta and Ludacris ('Little Bad Girl')—but we have a couple more on there that will be good surprises too."

A hangover  /ˈhæŋoʊvər/ is the experience of various unpleasant physiological effects following heavy consumption of alcoholic beverages. The most commonly reported characteristics of a hangover include headache, nausea, sensitivity to light and noise, lethargy, dysphoria, diarrhea and thirst, typically after the intoxicating effect of the alcohol begins to wear off. While a hangover can be experienced at any time, generally speaking a hangover is experienced the morning after a night of heavy drinking. In addition to the physical symptoms, a hangover may also induce psychological symptoms including heightened feelings of depression and anxiety.

Hypoglycemia, dehydration, acetaldehyde intoxication, and glutamine rebound are all theorized causes of hangover symptoms. Hangover symptoms may persist for several days after alcohol was last consumed. Approximately 25-30% of drinkers may be resistant to hangover symptoms. Some aspects of a hangover are viewed as symptoms of acute ethanol withdrawal, similar to the longer-duration effects of withdrawal from alcoholism, as determined by studying the increases in brain reward thresholds in rats (the amount of current required to receive from two electrodes implanted in the lateral hypothalamus) following ethanol injection. Dehydration is caused by alcohol's ability to inhibit the effect of anti-diuretic hormone on kidney tubules, which leads to an interruption of the body's Krebs cycle^{[citation needed]} and the swelling of the brain against the lining of the skull.

In music, a song is a composition for voice or voices, performed by singing. A song may be accompanied by musical instruments, or it may be unaccompanied, as in the case of a cappella songs. The lyrics (words) of songs are typically of a poetic, rhyming nature, though they may be religious verses or free prose.

A song may be for a solo singer, a duet, trio, or larger ensemble involving more voices. Songs with more than one voice to a part are considered choral works. Songs can be broadly divided into many different forms, depending on the criteria used. One division is between "art songs", "pop songs", and "folk songs". Other common methods of classification are by purpose (sacred vs secular), by style (dance, ballad, Lied, etc.), or by time of origin (Renaissance, Contemporary, etc.).

A song is a piece of music for accompanied or unaccompanied voice or voices or, "the act or art of singing," but the term is generally not used for large vocal forms including opera and oratorio. However, the term is, "often found in various figurative and transferred sense (e.g. for the lyrical second subject of a sonata...)." The noun "song" has the same etymological root as the verb "to sing" and the Oxford English Dictionary (OED) defines the word to mean "that which is sung" or "a musical composition suggestive of song." The OED also defines the word to mean "a poem" or "the musical phrases uttered by some birds, whales, and insects, typically forming a recognizable and repeated sequence and used chiefly for territorial defence or for attracting mates."

Jacob Taio Cruz (born 23 April 1983) known professionally as Taio Cruz (Portuguese: [ˈtaj.ju ˈkɾujʃ]) is an English singer-songwriter, record producer, occasional rapper, and entrepreneur. In 2008, he released his debut album Departure, which Cruz wrote, arranged and produced himself. It achieved initial success in the United Kingdom and earned him a MOBO Award nomination. In June 2010, Cruz released his follow-up album Rokstarr, which includes the number one singles "Break Your Heart" and "Dynamite". Cruz has collaborated with Kesha and Fabolous on the single "Dirty Picture", as well as Kylie Minogue and Travie McCoy on his single "Higher". Additionally, Cruz penned and recorded the song "Telling the World" as the lead single from the soundtrack to the 2011 animated film Rio.

Cruz was born in London, to a Nigerian father and a Brazilian mother called Beatriz Vitoria Olivera Bennati, from Rio de Janeiro. He attended Bilton Grange, a private prep school in Rugby, Warwickshire.

Tramar Dillard (born December 16, 1979) better known by his stage name Flo Rida (pronounced  /floʊ ˈraɪdə/), is an American rapper. He released his debut album, Mail on Sunday, in March 2008. His debut single "Low", featuring T-Pain, was a No. 1 hit for ten weeks in United States in early 2008. Two other singles resulted from Mail on Sunday: "Elevator" and "In the Ayer". In 2009, his second album R.O.O.T.S. was released; its most successful single "Right Round" was at the top of the Hot 100 for six weeks. Since then, he has released his third studio album titled Only One Flo (Part 1), which will see a sequel titled Wild Ones.