Jelly Roll has mocked President Donald Trump by referring to him as a “fat pig”.

The Grammy winner shared several jokes while guest hosting ‘Jimmy Kimmel Live!’ on Monday evening, including a remark that the weight he has lost in recent years equals an “entire Donald Trump”.

During his opening monologue, Jelly Roll, whose birth name is Jason Bradley DeFord, noted reports that the 80 year old president had recently gained weight and was “now tipping the scales at almost 240”.

“In the last few years I've lost 300lbs,” the 41 year old singer said. “That means I've lost an entire Donald Trump.”

The country rap musician continued, “And let's be honest, based on his approval ratings, it seems like most of the country wants to do the same thing”, prompting loud applause from the studio audience.

Jelly Roll then showed a compilation of Trump making fun of people’s weight, including clips in which he called former New Jersey governor Chris Christie “a fat pig” and “a big fat slob”. The singer described the comments as an example of “the pot calling the kettle fat”.

The ‘Save Me’ performer ended the segment by making a lighthearted joke about himself.

“Well, Mr President, from one fat pig to another, take it from me that physical fitness is very important,” Jelly Roll said.

He continued targeting Trump by joking about the president’s “s**t job” waving the starting flag at the NTT IndyCar Series Freedom 250 Grand Prix in Washington, DC, last Saturday. Footage showed Trump handling the green flag in a way that some viewers considered awkward.

“The president seemed to enjoy the IndyCar race, which was a real switch-up for him,” Jelly Roll joked, “because normally he only likes his own race.”

Jelly Roll is among six guest presenters selected to take over the late night programme during its summer break. The lineup also includes comedians Rosie O’Donnell, Tiffany Haddish, Anthony Anderson and Ike Barinholtz, along with actor and playwright Colman Domingo.