Pop superstar Taylor Swift endorsed Vice President Kamala Harris for president on Tuesday night, minutes after the Democratic nominee finished a contentious debate with Donald Trump.

"I'm voting for @kamalaharris because she fights for the rights and causes I believe need a warrior to champion them," Swift said in a statement posted on her Instagram account, which has more than 280 million followers.

"I think she is a steady-handed, gifted leader and I believe we can accomplish so much more in this country if we are led by calm and not chaos," Swift wrote, under a photo of her holding a cat.

"I was so heartened and impressed by her selection of running mate @timwalz, who has been standing up for LGBTQ+ rights, IVF, and a woman's right to her own body for decades," Harris said, referring to Minnesota Gov. Tim Walz.

Swift signed the post with her full name and as "Childless Cat Lady," a clear shot at Trump's Republican ticket running mate, Sen. JD Vance of Ohio.

Vance since his nomination in July has caught flak for comments he made in 2021 calling several key Democrats, among them Harris, miserable "childless cat ladies" who want to "make the rest of the country miserable too," as well as anti-family and anti-children.

Swift wrote that she was recently "made aware that AI of 'me' falsely endorsing Donald Trump's presidential run was posted to his site."

"It really conjured up my fears around AI, and the dangers of spreading misinformation," she wrote. "It brought me to the conclusion that I need to be very transparent about my actual plans for this election as a voter. The simplest way to combat misinformation is with the truth."

Two Harris campaign officials told NBC News that the timing of Swift's endorsement was a surprise to the campaign.

But the singer had endorsed President Joe Biden and his then-running mate Harris in the 2020 election.

Trump told reporters "I have no idea" when asked about Swift's endorsement of Harris on Tuesday.

"I've done my research, and I've made my choice," Swift wrote.

"Your research is all yours to do, and the choice is yours to make. I also want to say, especially to first time voters: Remember that in order to vote, you have to be registered!" she wrote.

"I also find it's much easier to vote early. I'll link where to register and find early voting dates and info in my story."