Clough said: "We are delighted for Johnny and proud he will be representing his country. It is no surprise - his knowledge of the game is second to none.
"He has added an extra dimension to our coaching staff and commands the respect of everyone at Derby County. He will be a big asset to them out in South Africa."
During his illustrious playing career, Metgod was capped 21 times by Holland between 1978 and 1983.