Bill Cosby has spoken out on the death of former co-star Malcolm-Jamal Warner.

Warner, who played the comedian’s son in the “Cosby Show,” died Sunday after drowning in Costa Rica at age 54.

“He was always a great studier, and I enjoyed working with him very much,” Cosby told ABC News.

“He was very professional. He always knew his part… He always knew his lines, and he always knew where to go.”

Warner, who was best known as Theo Huxtable, was caught in a strong current while swimming during a family vacation on Costa Rica’s Caribbean coast.

In the exclusive interview with ABC News, Cosby remembered Warner, who played his son for eight seasons on their hit show, as an ultimate professional.

Cosby told ABC News that he and Warner maintained a close relationship long after the show ended.

“Malcolm calls here regularly,” Cosby said, comparing his relationship to that of a mentor.Cosby, meanwhile, spent three years in prison for a 2018 sexual assault conviction, which was overturned on appeal.Mark Heim is a reporter for The Alabama Media Group. Follow him on Twitter @Mark_Heim. He can be heard on “The Opening Kickoff” on WNSP-FM 105.5 FM in Mobile or on the free Sound of Mobile App from 6 to 9 a.m. daily.