It all started when someone posted a video to Twitter of Penn Badgley doing press for the 1st season of "You." In it, Badgley discussed the use of social media and specifically highlights rapper Cardi B for the way she engages with it (via NME). "Cardi B is a great example of that," Badgley says of Cardi B's ability to use social media. "She has such an authentic relationship, and it's this incredibly nuanced place to be ... Despite what many might judge as antics and all this, I feel like she has an incredibly authentic relationship to that and that's why people like her so much."
The clip promptly went viral, and Cardi B reacted to it by tweeting, "OOOOMMFFFGGGGGG HE KNOWS ME !!! OMMMGGGG!!!!!! Yoooo like I'm famous famous." As a further sign of adoration for each other, Cardi B and Badgley proceeded to change their Twitter avatars to pictures of each other — Cardi's being of Badgley in character as Joe Goldberg.
Since then, fans want Cardi B to guest star in Season 4 of "You" (via People). In fact, there's even a Change.org petition going around to that effect.
As for what role Cardi B could play, she has it all figured it out. "So it's episode 1 and I'm at Paris Fashion week shutting it down! I turn around and there stands YOU," Cardi B wrote on Twitter. "Ok finish it off @netflix."