MMA star and YouTube street fighting sensation Kevin “Kimbo Slice” Ferguson has passed away at the age of 42 Monday, reportedly due to heart failure.

TMZ reported on Monday evening that Ferguson had been rushed to the hospital and was in a dire situation, and social media reports started to file in later that he had passed away. American Top Team, where Ferguson trained, confirmed the news on their Twitter account.

The ATT Family and South Florida community lost a legend today. RIP Kimbo. pic.twitter.com/sjs8ctyJMd

— American Top Team (@AmericanTopTeam) June 7, 2016

Ferguson rose to stardom on YouTube as a street fight legend, and parlayed that into an MMA career. He fought on the first-ever MMA event broadcast on network television — EliteXC: Primetime in May 2008 — where he defeated James Thompson. He famously lost to Seth Petruzelli later in 2008 in EliteXC’s final event. He went on to appear on UFC’s The Ultimate Fighter and fought Roy Nelson in the most watched fight aired on cable during that TUF season.

He went on to have a 1-1 record inside the Octagon, being released following a loss to Matt Mitrione.

Ferguson moved onto professional boxing and compiled a 7-0 record before returning to MMA with Bellator MMA. He defeated Ken Shamrock at Bellator 138 in June 2015, and followed that up with a second straight win in the infamous February bout against Dhafir “Dada 5000” Harris in February where Harris claimed he died during the fight and was hospitalized for several days following due to renal failure.

Ferguson failed a drug test afterward failing for nandralone and elevated testosterone levels. He was suspended for 90 days, far from the standard suspensions found in most states. Ferguson was booked to rematch Thompson at the upcoming Bellator 158 event on July 16 in London, England.

A statement from Bellator’s Scott Coker: 

We are all shocked and saddened by the devastating and untimely loss of Kimbo Slice, a beloved member of the Bellator family. 

One of the most popular MMA fighters ever,  Kimbo was a charismatic, larger-than-life personality that transcended the sport.

Outside of the cage he was a friendly, gentle giant and a devoted family man. His loss leaves us all with extremely heavy hearts, and our thoughts and prayers are with the entire Ferguson family and all of Kimbo’s friends, fans, and teammates.

A statement from UFC:

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UFC is saddened to learn of the passing of Kevin Ferguson, known to fans around the world as Kimbo Slice.

Slice will forever be a part of UFC history as a contestant on season 10 of The Ultimate Fighter in 2009, and for having fought twice inside the Octagon at The Ultimate Fighter Finale and UFC 113. He carried himself as a true professional during his time in our organization.

While he will never be forgotten for his fighting style and transcendent image, Slice will also be remembered for his warm personality and commitment to his family and friends.

UFC offers its sincere condolences to Slice’s family, friends and teammates at American Top Team.

Dave Meltzer and Bryan Alvarez have more on this on tonight’s Wrestling Observer Radio.