An image of former Vice President Joe Biden speaking with a homeless man in Washington DC has gone viral, being shared more than 100,000 times on Facebook.

The image was taken outside of an AMC cinema in Georgetown, with Mr Biden said to have been heading to see a film with his granddaughter, who was in the city visiting friends.

The photograph was taken by Caleb Baca on Thursday night, according to local television station Fox 5, but was posted into Facebook businessman Paul Equale, with that post being shared 103,000 times since it was posted on Friday - with more than 148,000 people reacting to it.

Mr Equale said in the post that “A bystander took [the] candid shot”. Speaking about Mr Biden, he added that “character is about what you do when no one is watching”.

“I'm not exactly sure what he gave the homeless man, but he appeared to write something down on a piece of paper inside the movie theater, which he then proceeded to give the homeless man outside,” Mr Baca told Fox 5.

Earlier in the week, Mr Biden was in Pennsylvania campaigning for Democrat Conor Lamb, who is battling Rick Saccone for a place in Congress in a special election in the Pennsylvania’s 18th district. He said that Mr Lamb reminded him "of his son Beau".

Mr Saccone is backed by President Donald Trump, who called him a “really good person” in a rally in the state on Saturday.