The 39 year old, real name Robert Diaz, became a staple in the underground hip-hop scene in his native New York in the 1990s and worked with the likes of Kweli, Royce Da 5'9, Immortal Technique and Jean Grae.

A cause of death has yet to be revealed, but the sad news emerges days after he and his wife announced they are expecting a daughter, their third child together, according to

Kweli led the tributes to his late pal on, where he shared a photo of Diaz and captioned it, "Just finding out I lost a great friend today. RIP Robert Diaz AKA Pumpkinhead. Robert and I went to PS 282 (school) together in Brooklyn, 4th grade. We then reconnected when he became an MC during the indie era of the late 90s. He signed to Makin Records, I signed to Rawkus. Then PH went on to reinvent himself again in the new battle rap era. He LOVED MCing and was great at it. To lose such a great human being so early in his life, man. No words. There is a fraternity of artists who were around for all of this. PH inspired us all. He will live on thru (sic) us even though his physical presence will be missed. RIP Robert Diaz."

Immortal Technique also shared his sadness on, writing "Rest in Power my old friend. Life is too short", while El-P adds, "aw man rest in peace, pumpkinhead. one of the coolest, kindest people to walk this earth."