Trump on preparing for first debate: ‘I don't know which Biden is going to show up’

President Trump on Tuesday said he “sort of” prepares every day for the upcoming general election debates with Joe Biden, while once again suggesting his Democratic rival should take a drug test ahead of the events to see whether or not he is “taking something that gives him some clarity.”

The president, during a wide-ranging interview with “Fox & Friends” Tuesday morning, was asked about the upcoming presidential debates. The first is slated to take place in Cleveland, Ohio on Sept. 29, and will be moderated by Fox News’ Chris Wallace.

TRUMP SAYS HE WANTS DRUG TESTS BEFORE THE GENERAL ELECTION DEBATES

“I sort of prepare every day, by just doing what I’m doing,” the president said, listing his travel for the week, noting he is crisscrossing the country form California to Texas, to Louisiana and Florida. “I’ve been all over the place, and I watch this guy sitting home, and I think, maybe I’m doing it wrong.” The president was referring to former Vice President Joe Biden, who he said “is always in Wilmington, Delaware” and stays in his basement.

“I don’t know which Biden is going to show up because I watched him during the debates, when they had 20 people on the stage … and I watched him and he was a disaster,” Trump said, referring to the Democratic primary debates. “You don’t get worse. He was grossly incompetent.”

The president, though, said that during the one-on-one debate on March 15 between Biden and former Democratic candidate Sen. Bernie Sanders, I-Vt., the former vice president was “OK.”

“I watched him against Bernie, he was OK, he wasn’t Winston Churchill, that I can tell you, but he was OK, he was fine,” Trump said.

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The president then went on to question whether Biden was taking medication to enhance his debate performances — a topic he has raised repeatedly in the past several weeks, while calling for a mandatory drug test ahead of the general election debates.

Trump offered no evidence to support his claims nor did he say what drug he thought Biden was taking.

“What did he do? What happened to him all of a sudden? Because, he was OK, it was an extraordinarily boring debate, but he got through it,” Trump said. “And I said, what’s the difference between now and some of those classic moments in the other debates, and something was strange in my opinion.”

He added: “I won’t say what, but a lot of people think something happens, but you can’t do that kind of stuff. You just can’t do that kind of stuff.”

Trump went on to say that he, too, would take a drug test ahead of the debates.

“I would take one too,” Trump said. “He’s taking something, or taking something that gives him some clarity … Maybe he had 15 cups of coffee.”

Trump continued, doubling down on Biden’s primary debate performance, while also taking a swipe at his running mate, Sen. Kamala Harris, D-Calif., who also launched a presidential bid this cycle.

“I’ve seen him in the debate with the other people, including Kamala, and nobody treated him worse than her, called him a racist … Kamala has her own problems, she dropped out before they got to Iowa. I think she’s not a good choice, compared to Mike Pence, who's been a great vice president,” he said.

TRUMP AGAIN SUGGESTS BIDEN USED DRUGS TO ENHANCE DEBATE PERFORMANCE DURING PRIMARIES

But Trump returned, again, to the topic of a drug test, calling it “very strange” and saying: “I think he should take a drug test.”

“Joe is lost, Joe is lost,” Trump said. “We can’t have a president that is mentally lost.”

Last month, the Biden campaign denied that the former vice president was on any drugs during the debates and blasted Trump as a liar.

"We know it’s unbelievable to Donald Trump, but Joe Biden can speak honestly without a shot of truth serum," Andrew Bates, a spokesperson for Biden's campaign, told Fox News. "We’d like to see Trump do the same.”

The early months of Biden’s third White House bid were marked by uneven debate performances and winding town halls in Iowa and New Hampshire. The floundering led to numerous stories about Biden’s gaffes and near-constant attacks from Trump about Biden’s mental fitness.

Since then, however, the former vice president has drawn praise for both his performance against Sanders in March and, more recently, for his speech at last week’s Democratic National Convention.

Fox News' Andrew O'Reilly and The Associated Press contributed to this report.