US actor Pernell Roberts, best remembered for his roles in Bonanza and Trapper John, M.D. has died of cancer aged 81.

Roberts appeared in Bonanza for six seasons as eldest son Adam Cartwright. The last surviving member of the classic Western’s cast, he left the show at the height of its fame.

For the next 14 years he mainly made appearances on TV shows and in miniseries, or toured with such theatrical productions.

In 1979 he found fame again in the playing Trapper John M.D., a spin-off from MASH, until 1986.  The MASH role was originally played by Elliot Gould and Wayne Rogers on film and television, respectively.

Roberts was well-known for his activism including pressuring NBC to refrain from hiring whites to portray minority characters.

He made his last TV appearance in 2001 on an episode of Diagnosis Murder.

Source: The Inquisitr, Press Association