The single was written and produced by Teddy Park and Kush, the song was released via digital download and streaming on May 12, 2011 by YG Entertainment.

[2] According to the CEO of YG Entertainment, Yang Hyun Suk, "2NE1’s new song counter feeds the people with an analogue sound unlike the majority who used strong electronics and house music and maybe that is why Will.i.am have [sic] found it interesting".

The song was not extensively promoted on music programs; but on May 29, 2NE1 made a surprise two-part performance on SBS's Inkigayo with "Lonely" and Bom's solo single "Don't Cry".

[8] "Lonely" was voted one of the top 8 idol hit songs of all time in a survey conducted by Research Panel Korea in 2013.

[9] Producers of the South Korean talent show Superstar K 4 (2012) noted that "Lonely" was track sung the most during auditions for the program in Sydney, Australia.

[16] Other artists who have covered it include Apink's Bomi, American singer Dia Frampton, Sungha Jung, and T-ara's Hyomin.