Kamala Harris and Donald Trump will roll out starkly contrasting celebrity back-up this weekend in Pennsylvania and Michigan -- among the most prized of the battleground states set to decide the tightest of US presidential races.
Pop star Lizzo will throw multi-Grammy award winning glitter behind the vice president's campaign in Detroit, while the world's richest man Elon Musk is to stump for Trump in Pennsylvania.
Harris will also be joined by R&B star Usher at a get-out-the-vote rally in Atlanta, Georgia, on Saturday.
Both candidates are fighting on every front to seal up voters' support in a race that polls suggest is effectively tied with fewer than three weeks to Election Day.
Musk, who endorsed Trump in July, is one of President Joe Biden administration's fiercest critics and has emerged as a loud voice in US politics since taking over Twitter, now known as X.
The Tesla and SpaceX CEO has taken an increasingly visible role in Trump's campaign and has donated almost $75 million to his political organization America PAC.
Harris has deployed high-wattage surrogates, from ex-president Barack Obama to Megan Thee Stallion since replacing Biden as the Democratic nominee in July.
Seeking to shift the polls in a desperately tight White House race, Harris has ramped up attacks on the mental fitness of the 78-year-old, who is the oldest presidential candidate in US history.
She questioned his ability to be president after Trump faced speculation that he is "exhausted" after backing out of a spate of interviews.
Politico reported that a Trump aide had told producers at a website negotiating an interview that the ex-president was "exhausted" and refusing some appearances -- a claim described by his campaign as "detached from reality."
Beyond the accusations, both candidates are spending their final campaign days in pivotal battleground states where early voting is already underway.
With less than three weeks to go, Harris has seen encouraging signs in her push for supporters to vote as soon as possible, as a bulwark against the traditional Republican edge among Election Day voters.
Almost 12 million votes had been cast by Friday evening -- around a third of them in the seven swing states expected to decide the election -- according to data tracked by the University of Florida Election Lab.
Georgia has been smashing records, while North Carolina reported a first day of voting Thursday that beat 2020, when there was a pandemic-linked surge in early ballots.
Where party breakdowns were available, registered Democrats accounted for roughly half of the total, while Republicans -- who have spent much of the Trump era casting aspersions over drop boxes and mailed ballots -- were responsible for around a third.
