OTTAWA -- Prime Minister Stephen Harper says Gov. Gen. David Johnston's term of office has been extended to September 2017.

Johnston was appointed to the vice-regal post in 2010 and the term is usually five years.

Harper says the extension will allow Johnston to take part in many of the events marking the country's 150th birthday in 2017.

Before his appointment as the country's 28th Governor General, Johnston was a lawyer, academic, and university administrator.

He is a former dean of law at the University of Western Ontario, principal and vice-chancellor of McGill University and president of the University of Waterloo.

The prime minister says Johnston has worked hard to advance Canadian interests at home and abroad.