Some on Twitter praised the way that Sanders, a 79-year-old progressive from Vermont who ran for president twice, managed to look like a common man even at the most historic events.

Others mocked his look for resembling a "grandpa at the post office" or someone going out to "shovel the driveway".

The images of Sanders sitting with his gloved hands crossed over his knees also sparked a wave of memes on social media.

Sanders remains a beloved political figure among progressive voters in the US, despite having failed to attain the Democratic Party's nomination for president.

Meanwhile, other high-profile political figures also saw their choice of outfit come under the spotlight.

Former first ladies Michelle Obama and Hillary Clinton, together with Vice President Kamala Harris, all wore varying shades of purple to the event.

Some speculated that the choice was a nod to a mix of blue and red, the colours associated with the Democrat and Republican Parties, symbolising a call for unity.

Harris often chose to wear purple during her campaign for the presidency in 2019.

It was meant to honour the late Congresswoman Shirley Chisholm, the first black woman to run for resident in the US, and who also wore purple during her campaign.

Australian Associated Press