Her husband, former President Jimmy Carter, who called her "an extension of myself" and has been in hospice care at home, was expected to attend the service at the Glenn Memorial United Methodist Church, his office said. Vice President Kamala Harris, former President Bill Clinton and former first ladies Melania Trump, Hillary Clinton, Laura Bush and Michelle Obama were also due to take part.

Rosalynn Carter was diagnosed with dementia, her family said in May. She died shortly after entering hospice care at home in Plains, Georgia, alongside her husband, a Democrat who gave his wife a prominent voice during his 1977-1981 presidency and supported her advocacy for the cause of mental health.

She lay in repose at the Jimmy Carter Presidential Library and Museum in Atlanta on Monday.

Her funeral will be held on Wednesday at the Maranatha Baptist Church in Plains, the Carters' small rural hometown, before an internment at the family residence.

Carter and her husband were the longest-married U.S. presidential couple, having wed in 1946 when he was 21 and she was 18.

Since his single term as president, Jimmy Carter has lived more post-White House years than any president before him, and Rosalynn played an instrumental role during those years, building the Carter Center nonprofit and the Habitat for Humanity charity.

(Reporting by Rich McKay in Atlanta and Jonathan Allen in New York; Editing by Cynthia Osterman)

By Rich McKay and Jonathan Allen