Rob Dyrdek just addressed the death of his longtime friend Christopher "Big Black" Boykin with a heartfelt message about the memories and time the two had together.
Rob posted a series of photos of the pair with the message, "My heart is broken. I don't want to write this post. I don't want to believe that this is reality. I am so thankful for you. We truly were brothers that lived an unexpected unforgettable adventure. I just can't fathom that it would end so suddenly."
TMZ broke the story ... Boykin died Tuesday, we're told it was of a heart attack.
Dyrdek added, "You will forever be in my heart."
Boykin was 45.