The song, which did not feature on the band's most recent album 'A Weekend In The City', will be given away in CD format in the November 14 issue of NME accompanied by three dance remixes, having had its video premier on the NME last week.
NME has issued a spate of single releases featuring some of the UK's most popular acts in the last six months, including vinyl covermounts for Babyshambles and The White Stripes. The NME said 'Flux' showed Bloc Party taking a more dance-oriented direction similar to the 1983 New Order classic 'Blue Monday'.
The covermount will be issued two days after its official UK release on November 12, while the remixed tracks will be streamed on NME.com.
Nick New, head of marketing at NME, said: "The cover design [for the issue] is also a really innovative treatment, and shows that to launch music in partnership with NME is very special indeed."
Kele Okereke, the Bloc Party frontman, said: "We're anticipating people will shriek and say 'what have Bloc Party done and where are the guitars?' But I think it's good to challenge your listeners. If you put ['Flux'] on in the middle of the night in any disco, I'm 100% [sure] that people will be carried by it."