Joe Biden has released a video showing him asking Kamala Harris to be his vice-president.

A long-time rival of Biden’s, 55-year-old Harris is the first black woman and South Asian American to be chosen for the role and will now look to help the Democrat into the Oval Office on November 3.

Harris has recently been extremely vocal about the need for reform in the police force following widespread anti-racism protests and the steep rise of the Black Lives Matter movement.

A video was released showing Biden calling Harris to offer her the role, with the words: "We are in a battle for the soul of this nation.

"But together, it's a battle we can win. @JoeBiden —I'm ready to get to work."

Meanwhile, Donald Trump immediately responded to the appointment by posting a campaign video labelling Harris a ‘phony’ and slamming his presidential rival.

During his daily press conference he wasted no time in attacking the Democrat’s choice for vice-president, saying: "She was very, very nasty... she was probably nastier than even Pocahontas to Joe Biden.

"She was very disrespectful to Joe Biden. And it’s hard to pick somebody that’s that disrespectful."

Harris and Trump’s vice-president Mike Pence will take part in a televised debate in Salt Lake City, Utah on October 7.

Biden and Harris will appear together for the first time publicly when they meet in Delaware on Wednesday to give speeches and attend a virtual grass-roots fundraiser.