Yesterday Lamar took to Instagram to preview the release.

The stunning comeback, which spears US President Donald Trump, also points to a possible release date in the closing bars: "I'll let y'all worry about a list, I'm on some other shit / a difference between accomplishments and astonishments / you know what time it is, ante up, this is in forever / y'all got 'til April the 7th to get ya'll shit together..."

"The Heart Part 4" is the latest in a series of tracks Lamar's kept up since 2010 - he's previously used the series to announce projects, including pulling a similar stunt to announce second record Good Kid, M.A.A.D City.

The lauded rapper, who headlines Coachella next month, is following up last year's untitled unmastered. demo compilation and 2015's seminal To Pimp A Butterfly LP.

Speaking to Rick Rubin in GQ late last year, Lamar said of the next record: "It's soon... I have ideas and I have a certain approach. But I wanna see what it manifests. I wanna put all the paint on the wall and see where that goes. Maybe you can help me with that."

You can get "The Heart Part 4" now from iTunes.