US pop star Taylor Swift has endorsed Vice President Kamala Harris as the country's next president.

She posted a message to Instagram on Tuesday shortly after a televised debate between the Democratic presidential nominee and Republican opponent Donald Trump.

Swift said she will be casting her vote for Harris and running mate Tim Walz in the 2024 presidential election.

She wrote that her decision was partially prompted by a fake image of her posted on Trump's social media account last month, which urged people to vote for him.

Swift 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 post carried a picture of Swift with her cat, and was signed, "childless cat lady." The phrase is a reference to a remark made in the past by Trump's running mate J.D. Vance, who described Harris and others as "childless cat ladies."

Swift has significant influence among young people, with more than 283 million followers on Instagram.