'Y'all think I'm kidding': Joe Biden says he's Kamala Harris' running mate

Republican critics of Democratic presidential candidate Joe Biden warn – without evidence, mind you – that the 77 year old will not actually be in control the White House, running mate Kamala Harris, 56, will be the de facto president.

On Tuesday, Biden joked about the claim – or was he joking?

 At the beginning of a campaign speech in Atlanta, Biden introduced himself.

"Folks, my name is Joe Biden, and I'm Jill Biden's husband and I'm Kamala's running mate," Biden said as people laughed. So he was joking, right?

Then Biden added: "Y'all think I'm kidding don't you?" 

The Trump campaign jumped onto Biden's comment.

"Joe Biden confirms what we all knew: 'I am Kamala's running mate. Y'all think I'm kidding don't you⁉️'" White House Press Secretary Kayleigh McEnany wrote on Twitter. "'KAMALA' sign is prominently displayed behind him."

President Trump and Republicans have often referred to Biden as a "Trojan horse" for the progressive wing of the Democratic Party, saying – again, without evidence – that Harris, rated the most liberal lawmaker in the Senate by GovTrack, will indeed run the White House.

Both Biden and Harris have blundered on who tops the ticket.

Harris last month touted the "Harris administration."

“A Harris administration, together with Joe Biden as the president of the United States," the California senator told Arizona business owners.

"And now, with a Freudian slip, she’s outright admitting it," Trump spokesman Jake Schneider wrote in an email to reporters after the comment.

Then Biden accidentally called it the "Harris-Biden administration."

“A Harris-Biden administration is going to relaunch that effort and keep pushing it further to make it easier for military spouses and veterans to find meaningful careers, to ensure teachers know how to support military children in their classrooms," Biden said during a veterans roundtable in Tampa, Florida, last month.