Stephen "Thundercat" Bruner -- a bassist, producer, singer and songwriter -- is a frequent collaborator of Kendrick Lamar and has worked with the rapper on his lauded sophomore album, To Pimp A Butterfly, and the majority of his new project untitled unmastered.

The Brainfeeder signee, who played bass and lent his vocals to several tracks on untitled unmastered., explains the significance of the project and why it hits just as hard as TPAB.

"I think [Kendrick] wanted to give people a gift," the 31-year-old tells XXL. "Or he wanted to give people something like the energy that they been saying they’re feeling around the album in a different way, which is like the embodiment of a creative spirit of the music. Then with To Pimp a Butterfly, he wanted to give people more to balance it out almost. To have an actual full scope of what it meant to do that album. The tracks from [untitled unmastered.], they hit just as hard in my opinion. It still is even a different inflection of how strong the message was on To Pimp a Butterfly album. It’s almost dealing more with him as a person himself."

Thundercat, who is most noted for working with Flying Lotus and winning a Grammy for his work on Kendrick's song "These Walls," got on the phone with XXL to discuss what he has planned for 2016, unreleased music with Kendrick, his appreciation for Pharrell's artistry and going to high school with Jay Rock.

XXL: How much unreleased material does Kendrick have?

Thundercat: Even me knowing the songs that still didn’t make it [to be released], there’s a couple of songs that I remember that ring out of my head a little bit because they were epic being recorded. To me, on a personal level, I was like, "Dang!" when it didn’t make it on the album. It wasn’t like “Why didn’t it make it on the album?” You kind of go, "Okay, I understand." He got a ton of stuff. I remember one time Terrance Martin playing me a track, I was sitting in a car and he playing me a track that he did and it was some real volatile stuff. I was just like, "Sheesh." Passing tones to get to the different parts to the gem we would call To Pimp a Butterfly. Nobody may ever hear it [laughs].

So what do you have planned for 2016?

I’m definitely working on a new album. I’m still working with Flying Lotus and hope to be working with a few other artists. Pharrell, I really, really would love to get a chance to work with him. He’s been my hero since I was a young kid. And I got a chance to tell him that. I was like, “Hey man, your N.E.R.D. album…” You don’t want to be the super stereotypical… "Your rap changed my life man” [laughs], but he was like, “Okay, cool, great.”

I really would love to work with Pharrell. I’m open to different ideas and just kinda keeping everything moving. Everything is kind of amped up so it kind of sharpens different senses for me. As an artist, it made me sit back and think for a second. Like the question you just asked. I’m in that mode, that mind state right now. I’m interested to see what is going to come for 2016. There’s still a lot of music being created and there’s music a lot of music that I’m involved in that hasn’t come out. It’s going to be interesting. But yeah definitely working on my new album.

How often do you work with the rest of TDE?

As weird as it is, they don’t reach out as much all the time [laughs]. I think it may be awkward because they feel like I work with Kendrick, so people may try and go. I don’t know if it’s weird. For a little while I was working with [Jay] Rock. I still would love to work with him. SZA, I just did that "Sobriety" song with her. Again, I would love to keep working with SZA too. I actually went to high school with Jay Rock. You want to know funny, Jay Rock was quiet in high school man. He was super [gang] bangin’. Me and him sat in Mrs. Bounders’ class and he would always laugh at how stupid I was. Somebody asked me a question and I was on my own merit doing something, he would just be like, “What’s wrong with you?”

I never forget walking, it was at the Kanye concert, and the whole crew, TDE was hanging out backstage at the Staples Center because he was opening for Kanye. Top Dawg introduced me to Jay Rock and I was like, “Jay Rock? What?” He was like, “Yeah man” [laughs]. I feel like there’s some magic to actually explore there but in due time it will be something that can be perused. I work a little bit with Punch. As we heard on that track, Punch is a monstrosity. I look forward to be working with him of course.

What’s you’re favorite N.E.R.D. album?

Deep down in your heard you know the answer to that. It’s In Search of...

I love Seeing Sounds too.

Yes, the one with the big gorilla on the cover. Put it this way, in a time when musicianship kind of was on the back burner, so to speak, that album kept me afloat creatively. It let me know the music still exist and it can be funky and it can be everything that it is supposed to be now and it’s okay. It was a natural thing. I remember sitting nights listening to that album.

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