Christopher "Big Black" Boykin and Rob Dyrdek showcased their unique friendship during Rob and Big — and following the tragic news of Big's death, the other half of the iconic duo paid tribute to his cohort and "brother."

"My heart is broken," Rob captioned the Instagram photograph with the late MTV star, above. "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. You will forever be in my heart."

The Ridiculousness host shared several additional images of his former bodyguard through their years of friendship, including a sweet snapshot of Big with Rob's son Kodah (while adding he was "so thankful for this moment"):

In addition, Ridiculousness' Chanel West Coast and Sterling "Steelo" Brim remembered Big with matching Instagram photos:

Big passed away on Tuesday morning; the cause of death was a heart attack. He was 45. He is survived by a 9-year-old daughter, Isis Rae Boykin.