Former President Jimmy Carter and his wife, Rosalynn Carter, made a surprise appearance in their Georgia hometown on Saturday -- having largely retreated from the spotlight amid health challenges.

The Carters went to the Plains Peanut Festival in what seems to have been their first outing since the announcement seven months ago that Jimmy Carter would receive hospice care. The couple previously attended two events last year.

"Beautiful day for President & Mrs. Carter to enjoy a ride through the Plains Peanut Festival! And just a week before he turns 99. We're betting peanut butter ice cream is on the menu for lunch! #JimmyCarter99," the Carter Center wrote on X, the platform formerly known as Twitter. (Peanut butter is a favorite of Jimmy Carter's.)

At 98, he is both the oldest living and longest-lived U.S. president. He will turn 99 on Oct. 1.

The former president's office announced in February that he had decided to receive hospice care following a series of short hospital stays. He had suffered multiple falls in 2019 and survived cancer in 2015.

In May, the Carter Center said the former first lady had been diagnosed with dementia. The Carters are also the longest-married presidential couple in American history, having wed in 1946.

The Carter Center launched a tribute earlier this month for the former president's upcoming birthday.

Jason Carter, the former president's grandson, recently said on "GMA3" that "we didn't know, and we didn't believe at the time, that we were going to get to this 99th birthday."

"They are coming to the end, of course, at this time in their lives. But they are at peace, they are together, they're at home, they're in love. And you don't get much more than that, and they don't expect more," he said.

"It's a true blessing for all of us to have had this much time with him," Jason Carter added.

ABC News' Matt Foster contributed to this report.