President Joe Biden is firing back at former President Donald Trump for seemingly confusing him with Vice President Kamala Harris.

In a post on Truth Social, Trump wrote, “Crooked Joe begins his “Big Boy” Press Conference with, “I wouldn’t have picked Vice President Trump to be vice president, though I think she was not qualified to be president.” Great job, Joe!

Biden responded on X by sharing a screen shot of the post, and writing, “By the way: Yes, I know the difference. One’s a prosecutor, and the other’s a felon.”

During a press conference on Thursday that was meant to reassure nervous Democrats about the president’s candidacy, a reporter asked, “What concerns do you have about Vice President Harris’ ability to beat Donald Trump if she were at the top of the ticket?”

“Look, I wouldn’t have picked Vice President Trump to be vice president if I didn’t think she was not qualified to be vice president,” Biden responded.

Biden’s flub with Harris was not even the first time on the same day he mixed someone up.

At an earlier event, he introduced Ukrainian President Volodymyr Zelenskyy as Russian President Vladimir Putin.

“Now, I want to hand it over the president of Ukraine, who has as much courage as he has determination. Ladies and gentlemen, President Putin,” Biden said.

After realizing his mistake, he added, “He’s going to beat President Putin. President Zelenskyy. I’m so focused on beating Putin, we’ve got to worry about it.”

Turning to Zelenskyy, he said, “You are a hell of a lot better.”