Sam Rivers, the founding bassist of Limp Bizkit whose low-end groove helped define the sound of late-1990s rap-rock, has died at the age of 48. The band confirmed his death Saturday in a statement shared to social media. A cause of death has not yet been made public.

“Today we lost our brother. Our bandmate. Our heartbeat,” Limp Bizkit wrote alongside a black-and-white photo of Rivers. “Sam Rivers wasn’t just our bass player, he was pure magic. The pulse beneath every song, the calm in the chaos, the soul in the sound.”

Born and raised in Jacksonville, Florida, Rivers first crossed paths with vocalist Fred Durst in the early 1990s while the two were active in the local rock scene. They briefly played together in a small band called Malachi Sage before linking with drummer John Otto, Rivers’ cousin, to form Limp Bizkit in 1994. Guitarist Wes Borland and turntablist DJ Lethal soon rounded out the group, creating a lineup that would bring rap-rock to the mainstream in the years ahead.

Rivers’ deep, slapping bass tone and fluid stage presence became an essential part of the band’s identity as Limp Bizkit began making waves beyond Florida. The group’s 1997 debut, Three Dollar Bill, Y’all, introduced their abrasive blend of hip-hop swagger and metal aggression, but it was their follow-up, Significant Other (1999), that catapulted them into superstardom. Driven by the single “Nookie,” the album debuted at Number One on the Billboard 200 and cemented Limp Bizkit as one of the defining acts of the era.

A year later, the band’s third album, Chocolate Starfish and the Hot Dog Flavored Water, opened with one of the biggest first-week sales figures in rock history and went on to sell millions worldwide. At the center of the chaos, amid Durst’s provocations and Borland’s theatrical visuals, Rivers anchored the sound with an unmistakable rhythmic precision.

While lineup changes and long breaks became part of Limp Bizkit’s turbulent trajectory, Rivers remained a constant through the band’s initial run and early-2000s hiatus. Outside of the group, he pursued production work and contributed to several projects, including the soundtrack for Queen of the Damned in 2002.

By 2015, Rivers quietly stepped away from touring, initially citing back problems linked to degenerative disc disease. Later, he revealed that he had been battling severe liver disease, a condition that ultimately required a transplant. In the 2023 book Raising Hell: Backstage Tales From the Lives of Metal Legends, Rivers recalled that period candidly: “I had to leave Limp Bizkit because I felt so horrible. A few months later I realized I had really bad liver disease. I quit drinking, followed the doctors’ orders, and got a liver transplant. It was a perfect match.”

After recovering, he rejoined Limp Bizkit in 2018 and resumed playing live. He remained with the group through their 2021 comeback album Still Sucks, their first release in a decade, and through recent recording sessions that included September’s single “Making Love to Morgan Wallen.”

Bandmates, collaborators, and fans flooded social media over the weekend to pay tribute. In a separate comment, DJ Lethal wrote: “We love you, Sam Rivers. Please respect the family’s privacy at this moment. Give Sam his flowers and play his basslines all day. We are in shock. Rest in power, my brother.”