New Delhi, Oct. 14 -- "RJ Mitte, my sweet son on Breaking Bad has died," Bryan Cranston wrote on Monday, and the actor who played Walter White Jr. for five seasons was 34.

32 p.m. but could not disclose a cause. The statement began, "It is with profound sadness that we share the tragic passing of beloved actor, philanthropist," and asked for privacy for his family and loved ones.

Mitte was 15 when Breaking Bad, the AMC Networks series, debuted in January 2008, and he stayed for all five seasons as Walter White Jr., the teenage son of a high school teacher turned methamphetamine producer. He had cerebral palsy, as the character did.

Cranston, who played his father, said he was in "deep despair." "I met him when he was only 14 years old,...