A star-studded line up took to the stage at Kamala Harris' presidential rally on Election Day Eve as they threw their support behind the current vice president.

Superstars Katy Perry and Lady Gaga performed a selection of their hits and endorsed Harris before Americans head to the polls today.

Katy roared onto the 2024 campaign scene to rally support for Harris at the event near Pittsburgh, where she performed after Harris left the stage having delivered her own stump speech.

The hitmaker, wearing a sparkly blue top and black skirt, started out by singing 'Dark Horse' and then declared 'my body, my choice' before singing 'Part of Me'.

Katy revealed becoming a mother four years ago is her reason for voting for Harris, saying: 'Orlando and I welcomed our daughter Daisy, and she is the reason I am voting for Kamala Harris.'

Katy shared that she has known Harris since before she was even a senator and that the vice president has always fought for the most vulnerable and will protect women's rights.

'I know she will protect my daughter's future, and your children's future and our families' future,' she added.

'We are not going back,' she yelled as she ended her set with Firework.

Right before Perry took the stage, Harris also spoke.

Contrary to critics' claims about the celebrity appearances, the vice president was clearly the main attraction. After Harris' exit, some people left before Katy even started her performance.

The vice president made her second to last stop on the day before Election Day near Pittsburgh, the state's second biggest and largest city in western Pennsylvania, where she asked attendees for their vote.

The vice president has been hitting an optimistic note in the final stretch, acknowledging for a second day that she has the momentum.

However, she warned 'the race isn't over, and we must finish strong.'

'Make no mistake, we will win,' Harris declared.

Lady Gaga glowingly introduced Harris' husband Doug Emhoff, praising his record of supporting women despite allegations of physically abusing a woman he used to date.

The pop star surprised Harris supporters at the rally and after playing 'America the Beautiful', she introduced the Second Gentleman.

'Now it is my privilege to introduce someone who knows how to support a powerful woman. The soon to be first first gentleman of the United States,' she said as the crowd cheered.

Emhoff's usually positive image took a blow after the Daily Mail reported allegations from a woman who said the First Gentleman slapped her in the face when they were dating, prior to his marriage with Harris.

Grammy winning singer and Oscar-nominated actress Andra Day, who is known for her portrayal of Billie Holliday, also performed earlier in the evening.

Day performed three songs including 'Rise Up' which was also used on the campaign trail by Hillary Clinton. She also performed a new song 'Empty' live for the first time.

Notably absent from the night's rallies was Taylor Swift, despite some hoping she would make a surprise appearance in Pennsylvania. Instead she was spotted at the Chiefs' game.

Christina also lent her vocals to Harris' election eve celebration with a performance at the MGM Grand Garden Arena in Las Vegas. 

Regional Mexican band Los Tigres del Norte and EDM duo Sofi Tukker also performed ahead of headliner Xtina.

During the night, she said: 'Tonight, I'm here in honor of the people who have fought to give us the privilege to be heard. Let's raise our voices and vote for freedom,' before launching into her song 'Fighter'.

She also performed Beautiful and her Pitbull collaboration, 'Feel This Moment'.