Biden stumbled as he climbed the plane's steps, initially appearing to trip, get up, then trip a second time. He struggled to get up the second time for a brief moment, before making it up, turning to wave at the top of the steps before hustling inside, CNN reported.
"So, as you know, it's pretty windy outside, it's very windy. I almost fell coming up the steps myself," she said while briefings reporters on the plane on the way to Atlanta. "He is doing 100% fine."
WATCH:President Biden trips on stairs boarding Air Force One
Jean-Pierre wouldn't say if he hurt the foot that was recently broken.
"He's doing great. All I can tell you is he's doing fine. He's preparing for the trip today and he is doing just great," she said in response to a question.
She repeated that he's doing just fine when asked if Biden got checked out by a doctor.
Biden had broken his foot in November, just after celebrated his 78th birthday and winning the White House, making him the oldest president in US history.
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During the 2020 campaign, the Biden campaign released a summary of Biden's medical history, which showed the former vice president was healthy and fit for the presidency.
Dr. Kevin O'Connor, who has been Biden's primary care doctor since 2009 and is the director of executive medicine at The George Washington Medical Faculty Associates, wrote at the time that Biden is "a healthy, vigorous" man "who is fit to successfully execute the duties of the Presidency."
Biden fractured his foot after he slipped while playing with his dog, Major. The Biden family has two dogs, Major and Champ, both German shepherds.
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