It is with great sadness that we report Christopher "Big Black" Boykin, who was the other half & star in Rob Dyrdek's hit MTV show "Rob & Big,” has reportedly died TMZ learned.

The cause of his death is still unknown at this time, but Chris’ reps say he died Tuesday morning. He was Rob's best friend and bodyguard on their reality show, which ran from 2006 to 2008, and also appeared on MTV's "Fantasy Factory" as well (see pic above).

Survived by a 9-year old daughter, Big Black was 45 years old. R.I.P.