Donald Trump has warned that pop star Taylor Swift will “probably pay a price” for endorsing his opponent Kamala Harris to be the next US president.

Swift stole the headlines after Tuesday’s presidential debate when she revealed she would vote for Harris in November and called the Democrat nominee a “steady-handed, gifted leader”.

But Trump, who was widely considered to have lost the sparring match with Harris but believes he won, dismissed Swift’s endorsement, saying he “was not a Taylor fan”.

“It was just a question of time,” Trump told Fox News on Wednesday (local time).

“She’s a very liberal person. She seems to always endorse a Democrat. And she’ll probably pay a price for it … in the marketplace.”

Asked if there would be a second debate after Harris called for a rematch, Trump said he would have to think about it.

“She wants it because she lost,” he said.

“She immediately said she wants another debate. You know what happens when you’re a prizefighter and you lose, you immediately want a new fight. You want a rematch.

“The guy that won is kind of happy and thinking about it.”

Musk’s ‘creepy’ offer to Swift

Trump supporter Elon Musk had something bizarre to say about Swift’s support of Harris – offering to give Swift a child after she signed off her post with “childless cat lady”.

“Fine Taylor … you win … I will give you a child and guard your cats with my life,” the billionaire tech mogul posted to X.

Musk’s tweet has been labelled “weird” and “creepy”, with people on social media wondering exactly what he meant.

“This tweet just takes things to a whole new level of strange. It’s not even eccentric at this point, just outright unsettling,” one X user said.

Said another: “You are creepy and weird.”

In a separate post, Musk remarked that Harris had “exceeded most people’s expectations” during the 90-minute televised showdown.

“While I don’t think the debate hosts were fair to Donald Trump, Kamala Harris exceeded most people’s expectations tonight.

“That said, when it comes to getting things done, not just saying nice-sounding words, I strongly believe that Trump will do a far better job.

“After all, if Kamala can do great things, why hasn’t she? Biden rarely shows up for work, so she’s basically in charge already.

“The question comes down to this: do you want current trends to continue for 4 more years or do you want change?”

The day after the presidential debate, Harris and Trump appeared alongside each other and US President Joe Biden and JD Vance to commemorate September 11.

The four political adversaries made a rare joint appearance at the New York City site that marks the terrorism plane attacks in 2001 that killed nearly 3000 people.

Harris and Trump shook hands and exchanged a few words despite their contentious debate the night before, then lined up for the commemoration.

Instead of formal remarks, the ceremony at the “Ground Zero” site where planes brought down the World Trade Centre’s twin towers included wives, husbands, sisters, brothers and grandchildren reading the names of family members killed 23 years ago.

Swift’s post on Wednesday to her 280 million followers was the biggest celebrity endorsement yet for Harris.

“I will be casting my vote for Kamala Harris and Tim Walz in the 2024 Presidential Election. I’m voting for Kamala Harris because she fights for the rights and causes I believe need a warrior to champion them,” Swift wrote.

Swift was pictured with her cat in the post, which she signed as “childless cat lady”, in a dig at Trump’s running mate JD Vance, who in a 2021 interview called some Democrats “a bunch of childless cat ladies”.

He has since said it was merely a “sarcastic remark”.

Swift said she was impressed by Harris’s running mate Tim Walz, who the singer described as someone “who has been standing up for LGBTQ+ rights, IVF, and a woman’s right to her own body for decades”.

Walz, who was on air on MSNBC when the endorsement was announced, said he was “incredibly grateful” and urged the singer’s large fan base of Swifties to “get things going”.

In August, Trump posted a fake social media image of Swift asking people to vote for him in the November election.

Swift referred to that on Tuesday, saying Trump’s move “really conjured up my fears around AI, and the dangers of spreading misinformation”.

“It brought me to the conclusion that I need to be very transparent about my actual plans for this election as a voter,” she said.

Swift has supported Democrats in the past and backed President Joe Biden in 2020.

Her endorsement is the latest for Harris from the entertainment industry.

Many Hollywood actors, producers and filmmakers have said they viewed Harris, a native Californian, as their hometown candidate.

-with AP