Bill Clinton said he was “not surprised” his ailing wife fainted at a 9/11 memorial service last Sunday in lower Manhattan, playing down her spell by claiming that with “walking pneumonia … sometimes you can’t walk.”

The former president discussed Hillary Clinton’s medical episode Thursday in an appearance to promote the 12th — and final — Clinton Global Initiative on Comedy Central’s “The Daily Show.”

“Well, you’re always concerned, but I was pretty sure I knew what it was because she had been working hard, she was dehydrated, she had been standing up a long time there, and, you know she wanted to go to that 9/11 ceremony, and we both thought it would be okay,” President Clinton told host Trevor Noah when he was asked whether he was concerned watching video of the fall.

Viral video appeared to show Hillary Clinton collapsing as she entered a Secret Service vehicle leaving the Sunday event.

“She felt good, but it’s not surprising,” Bill Clinton continued. “You showed that clip of President Obama in Philadelphia and somebody fainting, it happens a lot to me, and 90 percent of the time it’s just people are dehydrated, and, so, I didn’t worry too much about it. Sure enough, she got examined, that’s what the doctor said, but she also said she did have pneumonia. Used to be called walking pneumonia when I was young, but sometimes you can’t walk, you have to rest and that’s what she did.”

Noah also asked the former president how the possible future president is feeling. “Great,” Clinton responded in the Thursday night interview. “She looked great when she left this morning, and I turned on the TV and saw her in North Carolina, she looked great, and she just called and said she got home and she still feels good.”

Clinton added, “Big deal, she had pneumonia. People get it all the time.”