It started to gain some traction because of the actors, executive producer Matt Olmstead tells EW.
Shes looking for a real man, he qualifies.
Hes looking for a real soul, a real heart, and she qualifies.

Credit: Elizabeth Morris/NBC; Matt Dinerstein/NBC
We like those inter-show romances, Olmstead says.
They can be hard to facilitate scheduling-wise, but they do work.
The question remains how this new relationship will sit withFires Dawson (Monica Raymund).

In the middle of it you have his sister, who works with Brett, Olmstead says.
Well see where it goes.
The fourth season ofChicago P.D.premieres Wednesday, Sept. 21 at 10 p.m.
ET, while the fifth season ofChicago Firedebuts Tuesday, Oct, 11 at 10 p.m.