On Saturday night, the 52-year-old singer wowed and dazzled at the event, which took place across seven cities and six continents as an event for Global Citizen and Global Citizen's Recovery Plan for the World, a campaign to end COVID-19.
Performing live from New York City's Central Park, Lopez opened with an energetic performance of "Cambia el Paso." She was then joined onstage by LL Cool J for "All I Have," followed by Ja Rule for their hits "I'm Real" and "Ain't It Funny."
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Lopez's spectacular set also included fan-favorite "Jenny from the Block" and the unreleased song "On My Way" from her upcoming movie Marry Me, in theaters on Feb. 11.
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"It's always such an honor to be here with so many people, so many loving people, trying to do so many amazing things together," she said, as the crowd chanted her name. "And because of that, tonight I want to do something special."
"Do you guys mind if I do a song that no one has heard?" she asked the audience. "Because it's a special occasion, and I thought, 'What special thing can I do?' This song is about pushing through old mistakes and finding your destiny ... But this is just for you guys here tonight. I want to share this with you because I feel, I feel, what I know is that we are on our way."
Ahead of the event, a source told PEOPLE that Lopez put a lot of love into her performance, which streamed live on Global Citizen's website.
"Jen seemed excited as she arrived in N.Y.C. for the Global Citizen Festival. She had a long rehearsal Friday night with LL Cool J and Ja Rule," the source said. "She was energetic and looked amazing."
The insider added that getting to lend her talents to help out a cause like Global Citizen and aid those in need meant a lot to Lopez.
"She has been rehearsing at an LA dance studio with her team all week," the source said. "You can tell this is an important event for her."
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Meghan Markle and Prince Harry will also make their first joint public outing in months at the festival, "to continue their urgent work with world leaders in the pursuit of global vaccine equity to end the COVID-19 pandemic for everyone, everywhere," according to Global Citizen.
Harry, 37, and Meghan, 40, previously served as Campaign Chairs of Global Citizen's VAX Live: The Concert to Reunite the World, where Prince Harry gave an impassioned speech about the importance of vaccine equity.
The 24-hour broadcast from cities around the world is calling on G7 countries and the European Union to share at least 1 billion COVID-19 vaccine doses with those most in need and support calls for a waiver on COVID-19 vaccine intellectual property rights. The campaign is also calling on vaccine providers to share mRNA technology with the new World Health Organization-backed transfer hub based in South Africa.