Jimmy Carter joins the campaign trail for grandson Jason as he seeks to become governor of Georgia

It's been more than four decades since Jimmy Carter campaigned across Georgia and asked voters to make him governor.

His win set the stage for his election as president in 1976.

Carter has just turned 90, but he was out campaigning on Sunday for his grandson Jason, a Democratic state senator and lawyer from Atlanta who's challenging the Republican governor, Nathan Deal, on November 4.

The former president and his grandson spoke during a church service in south Georgia, a key area for Jason Carter as he looks to woo former Democrats back to a party that many left more than a decade ago. The visit to Mount Zion Baptist Church in Albany was part of a push ahead of early voting, which began overnight.

Jimmy Carter spoke of the struggle for black people to get the right to vote and praised his grandson for fighting against the state's voter identification law.

"He's led the charge," the former president said of his grandson's work in the courtroom to challenge the state law. "Everyone here and everyone you can contact should join with Jason when the time comes this year to make Martin Luther King's dream come true."