Celebrities Who Fought in Underground and Bare Knuckle Events
The underground fighting scene has always had a magnetic pull on celebrities. Some come to compete, some to invest, and some because the raw nature of underground fighting offers something mainstream combat sports cannot replicate. This is not a list of celebrities who dabbled in sanctioned boxing for a YouTube paycheck -- these are public figures who have genuinely engaged with the underground and bare knuckle world.
Alex Terrible -- The Death Metal Fighter
Known For: Vocalist, Slaughter to Prevail | Organization: Top Dog FC
Alex Terrible is the vocalist of Slaughter to Prevail, one of the most prominent death metal bands in the world. He is also a legitimate bare knuckle fighter who competed in Top Dog FC against trained opponents under bare knuckle rules -- not a gimmick, but genuine competition.
His appearances generated massive cross-pollination between the metal music community and the bare knuckle audience. A man who performs in a custom metal mask producing some of the most extreme vocals in music, competing bare knuckle in a circle of hay bales -- that is content that cuts through internet noise. His involvement demonstrated that the underground fighting aesthetic resonates naturally with the extreme music community.
Paige VanZant -- The UFC Star Who Chose Bare Knuckle
Known For: Former UFC fighter | Organization: BKFC
Paige VanZant was one of the most marketable UFC fighters before signing with BKFC in a deal that reportedly made her the highest-paid fighter on the roster. Her signing was front-page combat sports news and elevated BKFC's mainstream profile dramatically.
Her results have been mixed, but VanZant's impact transcends her record. She brought millions of eyeballs to bare knuckle who would never have watched otherwise. VanZant also competes in professional wrestling and maintains one of the largest social media followings of any active combat sports athlete, ensuring bare knuckle reaches audiences far beyond the sport's traditional fanbase.
Conor McGregor -- The Owner Behind the Scenes
Known For: Former UFC double champion | Organization: BKFC (ownership)
Conor McGregor has never fought bare knuckle, but his impact came through his wallet when McGregor Sports and Entertainment acquired a part-ownership stake in BKFC in 2024. The biggest name in combat sports history putting his money and brand behind bare knuckle legitimized the sport in a way no marketing spend could replicate. His global fame has opened doors for BKFC in media, sponsorships, and international expansion.
Demetrious "Mighty Mouse" Johnson -- The Backyard Ambassador
Known For: Former UFC flyweight champion (considered greatest MMA fighter ever) | Organization: The Scrapyard
Demetrious Johnson -- record 11 consecutive UFC title defenses -- appeared at The Scrapyard in Gig Harbor, Washington. Having the potential MMA GOAT attend a backyard fighting event was an enormous validation of the organization's approach to safety within an unregulated framework. His involvement collapsed the perceived distance between professional and underground worlds.
IShowSpeed -- The YouTube Phenomenon
Known For: YouTube creator (30M+ subscribers) | Organization: The Scrapyard
IShowSpeed's collaboration with The Scrapyard brought backyard fighting to an audience that skews significantly younger than the typical combat sports demographic. His viewers are young internet natives who consume content based on entertainment value rather than sporting pedigree -- and backyard fighting, with its raw energy and unpredictable outcomes, fits that consumption pattern perfectly.
Jorge Masvidal -- From Backyard to Promoter
Known For: Former UFC welterweight title challenger | Organization: Gamebred Bareknuckle MMA
Before becoming "Street Jesus" in the UFC, Jorge Masvidal participated in backyard fighting videos in Miami -- the same ecosystem as Kimbo Slice's content. After retiring from professional MMA, he founded Gamebred Bareknuckle MMA, the first professional bareknuckle MMA league, attracting former UFC fighters Junior dos Santos, Fabricio Werdum, Roy Nelson, and Anthony Smith. His journey from backyard fights to UFC to promoter is the most complete celebrity arc in underground fighting.
Artem Lobov -- The UFC Journeyman Reborn
Known For: UFC fighter, Conor McGregor teammate | Organizations: BKFC, Mahatch FC
Artem Lobov's UFC career was defined more by his McGregor association than his results. But he found his calling in bare knuckle, competing in BKFC -- including a notable bout against former boxing champion Paulie Malignaggi -- and later Mahatch FC, where a loss to Denys Berinchyk in July 2021 ended his career. Lobov showed that UFC veterans could build legitimate second careers in bare knuckle.
Dave Portnoy and Big Cat -- The Media Moguls
Known For: Barstool Sports | Organization: Rough N Rowdy
When Barstool Sports acquired Rough N Rowdy in 2017, Dave Portnoy and Dan "Big Cat" Katz transformed a small-town West Virginia boxing tradition into a national PPV phenomenon generating 41,000+ buys per event. Their irreverent commentary style defined the RNR viewing experience, proving that amateur fighting could be packaged as mainstream entertainment.
The Celebrity Pipeline
The thread connecting all these figures is the same: the underground and bare knuckle world offers something mainstream combat sports does not. For fighters like VanZant and Lobov, a second act. For musicians like Alex Terrible, a natural extension of an intense persona. For businessmen like McGregor and Portnoy, an investment in a rapidly growing niche.
The pipeline flows in both directions. Kimbo Slice used underground fame to reach the mainstream. Mainstream celebrities use the underground world to reinvent their brands. As bare knuckle continues to grow, the celebrity crossover will only accelerate.
For fighter rankings, see Top 10 Bare Knuckle Fighters of 2026 and Top 10 Underground Fighters of All Time.