Harris became the Democratic Party’s nominee in July following President Joe Biden’s exit from the 2024 presidential race. In August, Harris announced Minnesota Gov. Tim Walz as her running mate.

Swift mentioned Harris’ choice of Walz in her endorsement.

“I’m voting for @kamalaharris because she fights for the rights and causes I believe need a warrior to champion them. 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. 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,” Swift wrote.

“I’ve done my research, and I’ve made my choice. 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! 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.”

Swift signed off on the post by calling herself a “childless cat lady,” alluding to a phrase previously used by Sen. JD Vance, Trump’s running mate, to criticize Democrats.

In 2020, Swift announced her support for Biden and Harris in their bid for the White House.

Swift has spent most of her nearly two-decade career staying mum on politics until the 2018 midterms, when she endorsed two Democratic candidates out of Tennessee. She has since been vocally supportive of Democratic policies and candidates, often encouraging her supporters to vote and advocating for women’s rights, reproductive health and LGBTQ+ rights.

In her 2020 documentary “Miss Americana,” Swift expressed regret for not speaking up about political causes sooner, telling her father Scott Swift in an emotionally charged scene that she felt the need “to be on the right side of history.”

In another scene, she was critical of Trump.

A faction of Swift’s supporters –- known as Swifties -– have mobilized in the 2024 election cycle, forming a Swifties for Kamala community online shortly following Biden’s exit from the race and his subsequent endorsement of Harris.

The group, which Swift is not affiliated with and has thousands of followers on X, raised more than $122K during its two-hour kickoff call in August. Speakers included Massachusetts Democratic Sen. Elizabeth Warren and singer Carole King.

“We believe Harris-Walz will fight for our rights and the rights of our loved ones, and help make this country safer for everyone,” Carly Long, communications director of Swifties for Kamala, previously told CNN.

CNN’s Elizabeth Wagmeister and Kate Sullivan contributed to this report.