Geoffrey Pearson, the former Canadian ambassador to the Soviet Union and son of former Liberal prime minister Lester B. Pearson has died. He was 80.

Geoffrey Pearson, son of former prime minister Lester B. Pearson makes his way to his father's gravesite in Wakefield, Que., during a ceremony in 2001.
(Jonathan Hayward/Canadian Press)

Pearson died in his sleep, a family friend told the Globe and Mail. His cause of death is not yet known.

Pearson had an extensive career working for the government. He joined the department of external affairs of Canada in 1952, where he held a range of senior posts including Director-General of the Bureau of United Nations Affairs, and Adviser on Disarmament and Arms Control Affairs.

He served as a diplomat at Canadian embassies in Paris and Mexico City and at the High Commission in New Delhi.

From 1980 to 1983, he served as Canada's Ambassador to the U.S.S.R.

Pearson was also a former executive director of the Canadian Institute for International Peace and Security, serving in the role for six years. He also was president of the United Nations Association in Canada.

Pearson leaves his wife, former senator Landon Pearson and five children.