Kendrick Lamar’s historic Pop Out concert looked to include a very subtle but very telling reference to J. Cole, which went largely unnoticed.

Kendrick performed his 2015 smash “Alright” at Inglewood’s Kia Forum last week, but some close observers only recently discovered that the backing track he utilized was Cole’s remix, since the Dreamville rapper’s ad-lib could be heard throughout the entrance.

It’s probable that this was an olive gesture to Cole after the North Carolina native dissed Kendrick on “7 Minute Drill” in retaliation to his fiery line on Future and Metro Boomin’s “Like That.”

Cole made a U-turn just days later, apologized to Kendrick during his headlining performance at Dreamville Festival and later deleting “7 Minute Drill” from streaming sites.

Before their brief feud, the two had been longstanding friends and occasional collaborators, with Cole’s “Alright” remix releasing around the same time Kendrick dropped his 2014 Forest Hills Drive single “A Tale of Two Citiez.”

Cole also produced Kendrick’s 2011 hit “HiiiPoWeR,” and there have long been speculations that the two might collaborate on an album.

Cole has previously spoken about how close the fantasy project was to being a reality.

“In a nutshell, [Kendrick Lamar] had approached me at No ID’s after we had already established this relationship, and I had these beats at the time and was playing them for him,” he explained on Lil Yachty’s A Safe Place podcast last year.

“Was this our first time linking? “HiiiPoWeR,” one of their beats? I handed him a bunch of beats that I made. Some of them, perhaps, had a hook on them, a verse—this, that, and the third.

“So he took them, and we discussed, ‘Yo, dude, we should do a project.’ At the time, he wasn’t on, but I was fuckin’ with him.

Cole admitted that timing was a major reason why the record did not materialize: “At one point, it was a real thing.” But, due to time and life constraints, we’ll never get the opportunity to accomplish it properly.

“Time will be required for us to achieve our full potential. At least one year. When you have two successful artists with lives and families, it’s difficult to do.

He continued: “We put it to rest years ago. However, at one point, it was a genuine conversation. It’s not like there are tons of music. It’s not like there’s an album on the shelf somewhere.”