Kimbo Slice, who fought last February in a contest at Bellator 149, was taken to hospital on Monday in Florida but later passed away.
Details of the death of Slice, real name Kevin Ferguson, have yet to be released.
The CEO of Bellator MMA, Scott Coker, confirmed the news to celebrity website TMZ early on Tuesday.
“We are all shocked and saddened by the devastating 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.
“Our thoughts and prayers are with the entire Ferguson family and all of Kimbo’s friends, fans, and teammates.”
When signing a deal with promoter Gary Shaw, the iconic fighting figure competed seven times as a pugilist. Slice went unbeaten, scoring six knockouts before returning to MMA.
A friend to WBN from the start of his boxing career in 2011, Slice is the latest in a long line of high-profile deaths in 2016.
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