Former first lady Jill Biden said in a preview that was released Wednesday of an upcoming interview that she thought former President Joe Biden might have been having a stroke during the 2024 presidential debate.

The comment refers to the former president's poor debate performance, which ultimately led to him dropping his reelection campaign in favor of former Vice President Kamala Harris, who went on to lose to President Donald Trump.

Jill Biden described seeing her husband stumble through the debate as "frightening," and said it prompted concern that the then-81-year-old could have been having a serious health issue. 

"I was frightened, because I had never ever seen Joe like that before or since. Never," Jill Biden told CBS News Sunday Morning in an interview airing this weekend. "I don't know what happened. As I watched it, I thought, 'Oh, my God, he's having a stroke.' And it scared me to death."