The Simpsons actor Harry Shearer is to be replaced as the voice of Dr Hibbert, after the show said white cast members would stop portraying characters from other ethnic backgrounds.

Kevin Michael Richardson, known for his voice work on Family Guy and American Dad!, will take over in an episode that will air in the US this weekend.

Shearer had voiced the jolly medic, among other characters, since 1990.

He will continue to play Mr Burns, Ned Flanders and Principal Skinner.

The decision comes eight months after the show said white actors would no longer provide the voices of non-white characters, following particular criticism of Hank Azaria's voiceover of Apu.

Azaria had already said he was stepping down from playing the Indian-American shopkeeper. His replacement has not yet been revealed.

Last September, Azaria was also replaced as the voice of Homer Simpson's black workmate Carl Carlson. Actor Alex Désert took o

ver that role.

Last year, white actors also stopped voicing non-white characters in other animated US shows including Family Guy, Central Park and Big Mouth.