The choice of song was a throwback to Hathaway's 2004 film "Ella Enchanted," a jukebox musical in which the actress performs the track.
Hathaway also threw her support behind Harris at the event. "Hi, I'm Annie, and I'm a mom," she said, noting that her son Jonathan was there with her, according to a video shared on social media. "Also, in case you didn't know, I am voting for Kamala."
"Isn't it a relief to be decided?" Hathaway added. "It's very important to remember that America is a very big place, and not everybody is decided, especially in an election like this when passions are rightly so intense, because the stakes couldn't be higher. It's still very important to remember that you have to meet people where they are at, especially when you're canvassing and phone banking."
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Hathaway continued that Harris' supporters should contemplate a question that undecided voters may be asking, which transitioned into the first lyric from her performance: "Can anybody find me somebody to love?"
Near the end of the performance, Hathaway delivered another message about the presidential election.
"We've got a big choice to make, America," she said. "You do have to make a choice. You do have to vote."
Anne Hathawayon 'The Idea of You,' rom-coms and her Paul McCartney Coachella moment
Hathaway's throwback performance came after she revealed that a sequel to another one of her classic films, "The Princess Diaries," is in the works.
"Broadway Rallies for Kamala" was described as a gathering of Hollywood stars for a "special event to mobilize volunteers across the country to get involved in supporting" Harris' presidential campaign. Other celebrity attendees included Audra McDonald, Billy Porter, and Whoopi Goldberg.
In a speech, Goldberg urged supporters to "get on the phones, knock on doors, and explain to people what is in their best interests - not what they have to do, but what they should do for their families, for their children, for their friends, for the people they don't know," according to a YouTube video of the event.
The Princess Diaries 3' is coming,Anne Hathaway confirms: What to know about the film
Numerous celebrities have publicly thrown their support behind Harris in the weeks leading up to the Nov. 5 presidential election, including Taylor Swift, Billie Eilish and Bruce Springsteen.
A number of stars have also taken part in fundraisers for the Democratic nominee. In July, Jeff Bridges, Joseph Gordon-Levitt and Mark Hamill were among the actors who spoke during a Zoom call dubbed "White Dudes for Harris," which raised $4 million.
