Donald Trump has expressed enthusiastic admiration for Sydney Sweeney’s bold new jeans advertisement after discovering that the Hollywood actress is a registered Republican.

Shortly after finding out about her rumored political affiliation, the former US president took to Truth Social on Monday to call her American Eagle commercial the “‘HOTTEST’ ad out there.”

“Sydney Sweeney, a registered Republican, has the ‘HOTTEST’ ad out there,” he wrote.

“It’s for American Eagle, and the jeans are ‘flying off the shelves.'”

A reporter asked him about the Sweeney advertising campaign for American Eagle, pointing out that she was a Republican.

“She’s a registered Republican?” Trump asked. “Now I love her ad.”

“Is that right? Is Sydney Sweeney…,” Trump continued.

“You’d be surprised how many people are Republicans. That’s one I wouldn’t have known, but I’m glad you told me that.”

“If Sydney Sweeney is a registered Republican, I think her ad is fantastic,” the president concluded.

The ad has been accused of pushing and promoting a discredited agenda often adopted by white supremacists in the US.

Following Trump’s remarks, American Eagle’s share price jumped 20 per cent when Wall Street closed on Monday (Tuesday AEST).