RJ Mitte, best known for his role as the son of drug kingpin Walter White in the hit television series Breaking Bad, has died aged 34.
"It is with profound sadness that we share the tragic passing of beloved actor, philanthropist, and passionate disability rights advocate RJ Mitte," his representative said in a statement.
Mitte died on Monday, local time, in Brownsville, Texas. The cause of death was not disclosed.
A teenage Mitte first appeared in Breaking Bad in 2008 as the son of chemistry teacher-turned-meth dealer Walter White, a role that won lead actor Bryan Cranston global acclaim.
Mitte's character on the show, Walter "Flynn" White Junior, was based on a college friend of creator Vince Gilligan's, who died after graduating.
Mitte credited his role on the Emmy Award-winning series, which he starred in until the show's end in 2013, as his career breakthrough.
"When I first got the breakdown it said 'dark hair, big eyebrows and mild cerebral palsy' and I thought, 'That's me, oh my God, that's exactly me,'" he told the ABC in 2015.
"It was a role that gave me the opportunity to have a career … it gave me an outlet to speak on so many important topics."
Mitte was diagnosed with cerebral palsy aged three, a permanent physical disability that affects movement and posture.
Later in his life, he joined forces with the hospital where he was diagnosed, Shriners Hospitals for Children, as celebrity spokesperson for the anti-bullying campaign Cut the Bull.
"Cerebral palsy and mental health go hand in hand because when you have a physical disability you're twice as likely to be bullied," he said in 2015.
"With a physical disability you don't want to have to fight and it's not always pain-free, and I remember times when I didn't want to keep fighting, but I had no choice.
"I want to remind people not to be intimidated by their own fears, and if you think you can't do something, that's a lie to yourself."
Mitte was also an ambassador for United Cerebral Palsy and served as president of The Mitte Foundation, where he used his platform "to challenge stereotypes and promote greater representation for people with disabilities," his representative, Sean Reilly, said.
"Drawing from his own experience living with cerebral palsy, Mitte brought authenticity to the [Breaking Bad] role and built a platform on disability awareness and inclusion."
Breaking Bad, which ran for five seasons and won 16 Primetime Emmy Awards out of 58 nominations, has been widely credited as one of the best US series in recent times.