5 Colours in Her Hair was McFly's debut single, released in 2004 and reaching number one in the UK. Taken from the band's first album Room on the 3rd Floor, it introduced their guitar pop sound to a wide teenage audience and helped launch a long chart career. The title refers to a girl known for her constantly changing, multicoloured hair. Short clips of the intro and chorus still circulate in fan edits and nostalgia posts celebrating early 2000s British pop.