Keshia Knight Pulliam is paying tribute to her late Cosby Show costar, Malcolm-Jamal Warner . The actress, who was only six years old when she first starred as Rudy Huxtable on the sit-com, remembered her “big brother” in a poignant Instagram post a week after he tragically drowned at 54.

Malcolm-Jamal Warner’s “Cosby Show” family is mourning his death. Warner died at age 54 on Sunday, July 20, after drowning near a beach in Limón, Costa Rica. The actor was best known for playing Theodore Huxtable on all eight seasons of “The Cosby Show,” which aired from 1984-1992.

The Cosby Show alumna Keisha Knight Pulliam has paid a heartfelt tribute to her former The Cosby Show co-star Malcolm-Jamal Warner. In an Instagram post Sunday, Knight Pulliam wrote “A week ago I lost my big brother,

Actor and director Malcolm-Jamal Warner, best known for his role on "The Cosby Show," has died. Actor and director Malcolm-Jamal Warner, best known for his role on "The Cosby Show," has died at age 54 in an accidental drowning in Costa Rica,

Since then, Cosby has stayed out of the public eye, only making the occasional remark, including when his former costar Malcolm-Jamal Warner died on July 20. After Warner drowned in Costa Rica, Cosby's spokesperson Andrew Wyatt told PEOPLE that the actors kept in touch.

When audiences met Theo Huxtable, playing a high school freshman in 1984’s pilot episode of "The Cosby Show," his voice was squeaky, his room was a mess, and he was pleading with his dad, Heathcliff,