New York - Grammy-winning rapper Kendrick Lamar is set to release a new album next week with rock veterans U2 on the credits.
Lamar recently put out a song in which he boasted about himself and warned rival rappers: "You all got 'til April the 7th to get y'all shit together."
They will apparently have another week. Lamar did not release the album n Friday as widely anticipated, instead unveiling pre-order information for the still-untitled 14-track work.
The album will come out on 14 April - two days before Lamar headlines a night of Coachella, the major music festival in southern California.
The album's credits, made available upon pre-order, include U2 on track 11 - with frontman Bono identified by his real name Paul Hewson.
The credits could indicate a fresh track with the Irish rockers, who are preparing a new album of their own, or indicate that Lamar sampled or took inspiration from an existing U2 song.
Other artists credited include the English singer James Blake, Canadian hip-hop instrumentalists BadBadNotGood and rap producers Top Dawg and 9th Wonder.
Lamar's last full-fledged studio album, 2015's To Pimp a Butterfly, won wide acclaim for its lyrical reflections and musical experimentation, with its song Alright becoming an unofficial anthem of the Black Lives Matter movement.
Lamar last year unexpectedly released a companion album of demos from the recording sessions called untitled unmastered.