DETROIT, United States (AFP)— Pop star Lizzo appeared at a rally Saturday in her childhood hometown of Detroit to stump for Kamala Harris, encouraging early voting in the battleground state of Michigan that is crucial to the ever-tightening US presidential race.

The Grammy-winning artist called voting not a “love letter” but a “chess move” and said the Democratic vice president was the best option in the race against Republican Donald Trump, who was also set to tap star power in bringing out billionaire tech bro Elon Musk in Pennsylvania later Saturday.

Wearing a suffragette-white pantsuit as she addressed the crowd in Motor City, the artist Lizzo emphasised that “whether you’re a Democrat or Republican or neither, you deserve a president who listens when you speak.”

“You deserve a president who respects when you protest. You deserve a president who understands that their job is to be a public servant. And Kamala Harris has dedicated her entire career to public service,” the singer said.

Lizzo also drew cheers when urging listeners that America was more than ready for its first woman president, dropping a reference to her own hit song: “It’s about damn time!”

In brief remarks that followed, Harris cast herself as a leader for the people in contrast to her opponent, whose brash persona she dubbed “self-consuming.”

“We stand for the idea that the true measure of the strength of a leader is not based on who you beat down, it’s on who you lift up,” said Harris, who repeated her vows to invest in the working and middle classes.

The 59-year-old whose birthday is Sunday will also be joined by R&B star Usher at a get-out-the-vote rally in Atlanta, Georgia.

Both candidates are fighting on every front to seal votes 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 the 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 chief executive officer (CEO) has taken an increasingly visible role in Trump’s campaign and has donated almost $75 million to his political organisation America PAC.

Harris meanwhile has deployed high-wattage surrogates — from ex-president Barack Obama to rapper/ singer Megan Thee Stallion — since replacing Biden as the Democratic nominee in July.

Seeking to shift razor-thin poll margins in the White House race, Harris has ramped up attacks on the mental fitness of the 78-year-old Trump, who is the oldest presidential candidate in US history.

She questioned his ability to be president after the one-time real estate mogul faced speculation that he is “exhausted” after backing out of a spate of interviews.