Sanders' campaign has confirmed to ABC News that Sanders shot a video with Cardi aimed at young voters.
In a photo of the two that Cardi shared on Instagram, the rapper thanks the presidential candidate for answering questions from her followers.
"Not me, US," Cardi captioned the photo, which was taken where the video was filmed: at the TEN Nail bar in Detroit, Michigan, where tonight's Democratic presidential debate will take place.
"Thank you Senator Bernie Sanders for sitting with me and sharing your plans on how you will change this country," she continued.
"A couple of weeks ago I asked my followers if you had the opportunity to have a question answered by a democratic candidate what would it be...I selected the most popular questions to get answered."
She added, "Stay tuned to see how he will fight for economic, racial, and social justice for all. Together, let’s build a movement of young people to transform this country. LETS LEARN OUR CANDIDATES!"
Sanders captioned his photo of the two, "Today Cardi B and I finally met. We had a great conversation about the future of America. And let me tell you: Cardi B is right. Together, we’ll get millions of young people involved in the political process and transform this country."
There's no release date for the video yet.
Cardi actually hasn't come out and said she's voting for Sanders, but she tweeted about him in July, and said on a red carpet in April, "Imma always be with Bernie…Bernie don't say things to be cool. There's pictures of him being an activist from a very, very, very long time."