Former White House Doctor Says Barack Obama Criticized Him for Tweet on Biden's Mental Fitness

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Former White House doctor Ronny Jackson is alleging that Barack Obama once sent him a stern email after Jackson retweeted a 2020 video that reportedly showed then-presidential hopeful Joe Biden saying he was a "candidate for the United States Senate."

"Remember the cognitive test that I gave @realDonaldTrump? The one he aced! Sounds like somebody else might need some testing done!! Scary!!" tweeted Jackson, 55, who served as physician to the president under both Obama, 60, and successor Donald Trump, 76, from 2013 to 2018.

In his upcoming memoir Holding the Line: A Lifetime of Defending Democracy and American Values, out July 26, Jackson reportedly writes that Obama emailed him about the tweet within 20 minutes.

"I have made a point of not commenting on your service in my successor's administration and have always spoken highly of you both in public and in private. You always served me and my family well, and I have considered you not only a fine doctor and service member but also a friend," the email allegedly read, per multiple outlets including CNN and The Independent.

"That's why I have to express my disappointment at the cheap shot you took at Joe Biden via Twitter. It was unprofessional and beneath the office that you once held," Obama added in the email, per The Independent and CNN, citing Jackson's memoir.

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Patrick Smith/Getty Images Barack Obama (L) and Joe Biden

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The former president allegedly called Jackson's tweet "disrespectful to me and the many friends you had in our administration."

"You were the personal physician to the President of the United States as well as an admiral in the U.S. Navy. I expect better, and I hope upon reflection that you will expect more of yourself in the future," Obama reportedly added.

According to The Independent, Jackson writes in his book of how he felt following the email, "Screw that guy," referring to Obama: "I just walked away from it, which was the last time I had any contact with [Obama]."

A rep for Obama declined to comment, while Jackson's office did not immediately respond to PEOPLE's request for comment.

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Biden has been open about stumbling over words in the past, having spoken freely about his childhood years with a stutter.

The former vice president, 79, dismissed a 2020 question ahead of his presidential win about whether he has taken a cognitive test — an issue Trump, 76, pushed into the spotlight while boasting of his mental capabilities and attacking Biden.

"No, I haven't taken a test. Why the hell would I take a test?" Biden said during a clip from an interview with CBS News, shared by CBS Mornings.

"Come on, man," he continued. "That's like saying you — before you got on this program, you take a test where you're taking cocaine or not. What do you think? Huh? Are you a junkie?"

"I am very willing to let the American public judge my physical as well as my mental fitness," Biden also said at the time.