Madonna had a crowd in New York City singing and snapping along to a rendition of John Lennon's "Imagine" on Monday night — a final effort to galvanize support for Hillary Clinton.

Her surprise set came as Bruce Springsteen and Jon Bon Jovi also performed for the Democratic candidate at a rally in Philadelphia.

The performances followed a collection of younger artists who campaigned for Clinton in Cleveland on Friday, including Beyonce, Jay-Z, J. Cole and Chance the Rapper.

SEE ALSO: Dog dressed as Madonna will totally win the costume contest

Madonna took a more laid back acoustic approach to her endorsement. Wearing a patriotic beanie, she stood before a sea of New Yorkers for the impromptu performance in Washington Square Park.

Madonna for Hillary. NYC pic.twitter.com/0Up2CoSm76 — Adam Parkhomenko (@AdamParkhomenko) November 8, 2016

Pop up Madonna concert in the middle of the fountain in the middle of Washington Square Park is reason #737209123 why I LOVE NEW YORK. pic.twitter.com/L9U6ctHH4g — Liz Pierson (@liz_pierson) November 8, 2016

From the Greenwich Village backdrop to the Lennon lyrics, Madonna's performance was a quintessential New York moment meant to help elect the state's one-time senator as president.

You May say I'm a Dreamer.......... But I'm not the only one! 😂🙏🏻🇺🇸 Vote for H.R.C.🇺🇸 pic.twitter.com/9jP0fb97ZM — Madonna (@Madonna) November 8, 2016

The occasion was made all the more special by its spontaneity, with Madonna first promoting the free concert just days earlier. She tweeted out the location and other details just an hour before hitting the park.

Bitches Are You In My Gang??? Doing a surprise intimate very small acoustic concert Monday night in support of Hillary. Stay tuned! 🎉🎉🎉😂 pic.twitter.com/ZYf8X8aG1A — Madonna (@Madonna) November 5, 2016

Meet me in Washington Square Park at 7:30 Let's Go Hard For Hillary Clinton! 🇺🇸🙏🏻🎉🎉🎉🎉🎉🎉🎉🇺🇸🇺🇸🇺🇸🏃🏃🏃🏃🏃🏃 pic.twitter.com/3czBXlaWsR — Madonna (@Madonna) November 8, 2016

Monday night's pop-up concert wasn't the first time Madonna's showed some love for Clinton. Her Twitter account has been an active realm of support for the Democratic candidate for some time.

She's also had some choice words about Republican presidential candidate Donald Trump.