Stanley Johnson told France’s RTL radio that he had always regarded himself as French as his mother was born there.
The 80-year-old former Conservative Member of the European Parliament voted Remain in the 2016 Brexit referendum.
His son Boris spearheaded the Leave campaign and later took the UK out of the EU as prime minister.
“It’s not about becoming French,” he told RTL. “It’s about reclaiming what I already have.”
He pointed out that his mother was born in France to a French mother. “I will always be European,” he added.
Stanley Johnson won a seat in the European Parliament when direct elections were first held in 1979, and later worked for the European Commission. As a result, Boris spent part of his childhood in Brussels.
Brexit issues have divided the Johnson family. The prime minister’s sister, the journalist Rachel Johnson, left the Conservative Party to join the Liberal Democrats ahead of the 2017 election in protest against Brexit.
Their brother, the Conservative MP Jo Johnson, resigned from the cabinet in 2018 to highlight his support for closer links with the EU.