Hip-hop fans and artists are mourning the unexpected death of influential hip-hop DJ Big Kap, who died today (February 3) at the age of 45 from undisclosed causes. According to a post on his Instagram page, he was scheduled to perform today. 

For those who don’t know, Big Kap (born Keith Carter) was an important presence in New York City’s hip-hop world, best known beyond the five boroughs for ”The Tunnel,” his 1999 collaborative album with DJ Funkmaster Flex. The album is a portrait of popular rap at the time, with verses from Jay-Z, Snoop Dogg, DMX and myriad others. It also featured a rare live freestyle battle between 2Pac and Biggie. Big Kap was influential in launching Biggie’s career, serving as his DJ during the infamous 1995 Summer Jam performance where Biggie threw a water bottle at Kap (though Kap later claimed that there was no bad blood).

Flex broke the news of his passing via an Instagram post, and hip-hop heavyweights responded in kind with their own condolences, helping make Big Kap a trending topic on Twitter:

RIP, Big Kap. 

(H/t New York Daily NewsAllmusic.comThe SourceThe Fader)