Hillary Clinton endorses Joe Biden for US president against her former rival Donald Trump

She is expected to boost Biden’s popularity with women as he faces a sexual misconduct allegation

Former secretary of state Hillary Clinton was also targeted in the posts. AP

Former US secretary of state Hillary Clinton endorsed Democratic presumptive candidate Joe Biden on Tuesday, adding her voice and political influence behind the former vice president.

Ms Clinton endorsed the former vice president in a joint online campaign gathering.

"I am thrilled to be part of your campaign, to not only endorse you but to help highlight a lot of the issues that are at stake in this presidential election,” she said.

“I’ve been not only a colleague of Joe Biden’s, I’ve been a friend and I can tell you that I wish he were president right now."

The two discussed economic policies, gender equality and the US response to the coronavirus pandemic.

Ms Clinton called for “radical transparency” in how the US government works to restore trust and counter disinformation campaigns.

Earlier, Ms Clinton tweeted a teaser on joining an online rally hosted by the Biden campaign as a surprise guest.

She used an old photo of the two of them sharing a hug in the Oval Office with former president Barack Obama gesturing in the foreground.

Mr Biden shared the tweet with the caption: “I am with her.”

That was Ms Clinton’s campaign slogan in 2016 when she ran and lost to US President Donald Trump.

During the online gathering, the former first lady criticised Mr Trump without mentioning his name, saying he had dismissed science in his response to Covid-19.

“Just think of what a difference it would make right now if we had a president who not only listened to the science [but] showed the kind of compassion and caring that we need from our president, and which Joe Biden has been exemplifying throughout his entire life,” Ms Clinton said.

Mr Biden responded: “I really appreciate your friendship."

The endorsement and Ms Clinton's celebrity status in the Democratic Party add momentum to the Biden campaign and show a unified front by its leading figures behind the apparent nominee.

Mr Obama and senators Bernie Sanders, Elizabeth Warren, Amy Klobuchar, and Kamala Harris have already endorsed Mr Biden.

Ms Clinton has been scathing in her criticism of Mr Trump on Twitter, describing his Covid-19 handling as a “botched response” and asking for “the damn tests” the administration had promised early on.

Her endorsement is also expected to help Mr Biden with women voters, given her track record as an advocate of women’s rights and the first female candidate in a US election.

But he is facing an allegation of sexual harassment from a former staffer, Tara Reade, who worked for him in the 1990s.

His campaign has denied any wrongdoing but he has not personally addressed the issue.

Mr Biden is seeing a rise in the polls against Mr Trump for the November 3 elections.

National coronavirus cases have passed a million and more than 57,000 patients have died, hurting the incumbent’s chances.

With Ms Clinton’s endorsement, all rumours of her own third campaign have gone.

Former first lady Michelle Obama could weigh in next, along with former presidents Bill Clinton and Jimmy Carter.

The Biden campaign will soon launch a committee to pick a candidate for vice president.

Mr Biden has promised to pick a woman as his deputy, and Ms Harris, Ms Klobuchar, Ms Warren and Senator Catherine Cortez Masto are believed to be on the shortlist.

Also among those favoured are Gretchen Whitmer, the Governor of Michigan, and Georgia politician Stacey Abrams.

But the pick may not be announced until later in the summer and before the party conventions in August, where Mr Biden and Mr Trump will be officially nominated.