US Vice President Kamala Harris will make the most important speech of her political life on Thursday when she accepts the Democratic Party's nomination for president a month after the party forced President Joe Biden to exit the race.

Harris's own presidential ambitions were always clear, but had been undermined by her own shaky 2020 campaign and bumpy vice presidential term. Since being thrust to the top of the ticket, she has tightened the race against Republican Donald Trump.

Her forceful stump speeches have been met by a surge in enthusiasm from voters. If Harris wins on November 5, she will be the first Black, South Asian woman elected president.

In her speech Harris, 59, plans to talk about her life as the daughter of a Jamaican father and Indian mother and lay out her plans to tackle rising costs and advance personal freedoms, including abortion rights, aides said.

They said she will also deliver a robust denunciation of former president Trump.

"There is a guy who wants to divide us, and she will make the case that we simply cannot let that happen, that this is America and everybody can rise together," Cedric Richmond, campaign co-chair and longtime adviser to Harris, told Reuters.

Convention delegates got a preview on Monday, the convention's first night, when Harris unexpectedly walked out on stage to the tune of Beyonce's "Freedom."

"This November we will come together and declare with one voice as one people: We are moving forward," she said.

Whether Beyonce will appear on stage on Thursday is a matter of speculation in convention hallways. The campaign declined to comment.

Harris has raised a record-breaking $500 million in a month and has narrowed the gap or taken the lead against Trump in many opinion polls of battleground states. Nationwide, she leads Trump 46.6% to 43.8%, according to a compilation of polls by FiveThirtyEight.