A change in John Fetterman's appearance, which has seen the Pennsylvania senator shave his trademark beard and grow a moustache, has sparked a wild conspiracy theory online that he may have been replaced with a double.

The claim has been made by a number of Donald Trump-supporting influencers, with one claiming it proves the American government "uses doubles."

In November 2022, Fetterman was elected as a Democratic senator, defeating Trump-endorsed Republican Dr. Mehmet Oz in a tightly fought contest, which helped the Democrats maintain control of the upper chamber.

On Saturday Fetterman posted a photograph on X, formerly Twitter, showing he had removed his iconic goatee beard, and grown a spruce moustache. In reference to his 13-year-old son, he wrote: "Lost a bet with Karl" followed by the "disgusted face" emoji. The post was widely shared, receiving over 950 reposts and 1.9 million views.

Later the same day Gisele Barreto Fetterman, the senator's wife, posted a photo of the couple with the caption: "Date night (ps. I never knew he had a chin."

Asked what the bet had been about she replied: "Chess, always chess."

However, online influencer Stew Peters took a different view. He shared the new photo of Fetterman, wearing a plain shirt and glasses, alongside an older one of him in a suit with his beard. He wrote: "The guy pretending to be John Fetterman looks nothing like the real John Fetterman. Ears clearly don't match."

Jack Danger, a self-styled "Twitter influencer" and part of the MAGA (Make America Great Again) movement, shared the same side-by-side comparison, commenting: "For those of you who still don't believe the U.S. government uses 'doubles' despite all the evidence of Joe Biden & others, & for those of you who are on the fence, I give you actual evidence. They are trying to pass this person off as John Fetterman. Look at the ears."

A third X account, with more than 34,000 followers, posted side-by-side shots of Fetterman along with President Biden, actor Jamie Foxx and philanthropist Melinda Gates. He wrote: "Just a few examples of how they are using doubles to fool the masses."

Hi-Rez, a Trump-supporting rapper with 137,000 X followers, shared a video of a man claiming he had uploaded two photos to a "biometric scanning website," from before and after he grew the moustache, showing only a 39 percent match. He added: "John Fetterman is a clone," followed by a tears of joy emoji.]"

No other "evidence" has been presented to support the wild claims.

Gisele hit back at the conspiracy claims, commenting: "Thinking there may be something to the body double rumors ... suddenly 'John' is closing kitchen cabinet doors. WHO IS HE," alongside an eyes emoji.