Drake dropped the diss track “Back to Back” in July 2015 at the height of his beef with Meek Mill. The song would go on to earn a Grammy nomination for Best Rap Performance in 2016 and hit No. 21 on the Billboard Hot 100. It was a huge look for up-and-coming Toronto producer Daxz, who was credited as the lead producer with co-production by Noah “40” Shebib and Drake. However, there was another budding Toronto artist involved in the track: NAV.

The XO signee’s contributions to “Back to Back” aren’t exactly a secret; shortly after it dropped, he publicly thanked Daxz for letting him be a part of the song in a now-deleted tweet.

He’s also listed as a songwriter/composer—under his given name Navraj Goraya—by BMI, a music rights organization. However, his work on the song has gone largely overlooked, likely because he wasn’t well-known at the time. XO only announced NAV’s signing back in February, and he saw his first high-profile production credit on Travis Scott’s late-2016 track “Beibs in the Trap.”

Daxz got most of the press attention, explaining in an interview with Complex that he met Drake in the studio for the first time the day he sent 40 the “Back to Back” beat; they dropped the song later that night.

It’s not clear what NAV contributed to the track as Daxz doesn’t mention him being in the studio that night, but it seems likely that NAV worked on the beat before the song was recorded. A tweet from NAV indicates that he worked with Daxz shortly before “Back to Back” was recorded and released:

The day it dropped, NAV asked Daxz for clarification about the song’s beat, although it’s unclear if his chords were ultimately used:

You can read all the lyrics to Drake’s “Back to Back” on Genius now.