Some were quick to declare Lorde as queen
of green.
Others even drew parallels with the iconic green light in The Great Gatsby.
The upbeat track is markedly different from the dark, brooding atmosphere that dominated Pure Heroine, which fans picked up on.
In less than an hour after the song was released, #greenlight was trending on Twitter, and the video had already gathered more than 100,000 views on YouTube.
Lorde announced on Friday morning that her upcoming album is called Melodrama, and posted the artwork on Instagram.
No release date has been given.
Green Light was co-written and produced with Jack Antonoff and Frank Dukes. Antonoff appears in the video, which is directed by Grant Singer.
The singer said the song was "kind of a curve ball", and that the album is "very diverse".