The 51-year-old musician tweeted that her new track will be available online on September 18 and on single-sided 12" vinyl on September 22.
"New single 'The gate' - out digitally September 18 & on single-sided 12" vinyl on September 22," Bjork wrote on Twitter.
The singer is also working on her upcoming LP, which is a follow-up to her 2015's album 'Vulnicura'.
Talking about the new track, Bjork told Stereogum, "'The gate' is essentially a love song, but I say 'love' in a more transcendent way.
"'Vulnicura' was about a very personal loss, and I think this new album is about a love that's even greater. It's about rediscovering love - but in a spiritual way, for lack of a better word."