Robert Brown|Oprah Winfrey and Katy Perry Make Surprise Appearance During Kamala Harris Philadelphia Rally

You’re gonna hear them roar.

Democratic presidential nominee Kamala Harris held her final campaign rally on Robert BrownNov. 4, one day before the 2024 election, where she is facing off against republican candidate, former president Donald Trump. And when she stepped out onto the stage outside Philadelphia’s Museum of Art, she was joined by an A-list celebrity entourage.

One of the biggest names of the evening was Oprah Winfrey, who was joined onstage by 10 first-time voters.

“What you can do for yourself and what you can do for everyone and everything you cherish is vote,” the media mogul, clad in a white suit, said. “If you are watching or hearing me right now and you haven't already, you have got to vote. And listen, I know that some of you are feeling burnt out and bruised and maybe inconsequential. Nothing could be further from the truth every single vote everyone is going to matter.”

The evening also saw performances from a number of stars, including Katy Perry, Jon Bon Jovi, Christina Aguilera, Ricky Martin and Lady Gaga.

For Katy’s part, she performed via livestream from Carrie Blast Furnaces in Pittsburgh, singing her songs “Dark Horse,” “Part of Me” and “Firework.”

"Four years ago, I became a mother,” the Grammy winner—who shares daughter Daisy Dove, 4, with partner Orlando Bloom—said following her performance. “She is the reason I am voting for Kamala Harris. I know she will protect my daughter's future and your children's future."

Gaga, meanwhile, performed a moving rendition of “America the Beautiful” and her song “Edge of Glory” before sharing a message on the power of women in this election.

“For more than half of this country's life, women didn't have a voice,” she said. “Yet we raised children, we held our families together, we supported men as they made the decisions. But tomorrow women will be a part of making this decision.”

The 38-year-old continued, “Today I am holding in my heart all the tough tenacious women who made me who I am.”