The world of Unbreakable Kimmy Schmidt has a loose grip on reality, so it shouldn’t surprise that famous faces occasionally pop up in-character. That said, crossing over with a fellow Netflix universe is another matter entirely, as producer Robert Carlock explains how the Kimmy crew made a certain prison transfer happen in Season 3.

You’re warned of full spoilers for Unbreakable Kimmy Schmidt Season 3, but it might surprise you to learn that Kimmy has been brightening the Orange Is the New Black universe this whole time. The third season’s fifth episode saw Kimmy’s bunker-mate Gretchen (Lauren Adams) taken to a familiar prison; entering the Litchfield gates alongside Orange player Black Cindy (Adrienne C. Moore).

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The footage was partially recycled from Orange Is the New Black itself, as executive producer Robert Carlock explained to Entertainment Weekly how the gag came about:

We didn’t want to blow up Gretchen or any of the people around her, so we knew she was going to jail. I think [the OITNB scene] was just half a joke pitch and half we felt we could somehow save money, and that turned out not to be true. And, it turned into purely a joke that I think was Tina [Fey]’s. We thought it was funny to suggest we lived in that same world as Orange Is the New Black, and of course, we’re always looking for Netflix synergies. […]

We emailed Jenji Kohan just asking if it was okay that we said she was going to that prison, and then I think we added the idea of, “Oh, it’d be nice to have one of their actors to make it really real.” And, we asked if that was okay. Jenji was very open to us just trampling all over the world she created, which we were very appreciative of.

The writers were also careful not to step on too much continuity:

At one point, the line that Black Cindy has‚ which is about stabbing her boss at Sea World, was phrased where it made it seem like that was the reason she was at that prison, which pulled a little thread. Jenji did ask us to make that something that happened in the past, which was fine with us and completely understandable … I don’t know that Jenji will allow us to do a Gretchen episode of Orange Is the New Black, but we just like the idea of these fictional worlds intersecting.

Intriguingly, Moore appeared on 30 Rock in two separate Season 7 roles, to which Carlock joked that “in our unified field theory, the character she played on 30 Rock is now in prison and worked at Sea World.” To add even more of a headache, Kimmy’s version of Cindy was arriving at Litchfield in 2017, despite Orange Is the New Black debuting in 2013, and supposedly taking place over Piper’s 15-month sentence. Cindy might also turn on the TV to find a weatherman that looks suspiciously like C.O. Humphrey.

Want to get crazier? Carlock also referenced the unused Season 3 crossover that would have seen 30 Rock’s Kenneth putting in a cameo, even as the newest Kimmy episodes added Judah Friedlander, John Lutz, Scott Adsit, Chris Parnell and more to the ranks of 30 Rock alum playing different roles. Then there’s Orange Is the New Black apparently sharing dreamspace with Black Mirror, and … well, now I’ve gone cross-eyed.

In the meantime, all Unbreakable Kimmy Schmidt episodes are available on Netflix, with Orange Is the New Black Season 5 set to premiere on June 9.