While "Chicago P.D." stars Tracy Spiridakos and Marina Squerciati have clearly spent most of their professional careers for the past several years within shouting distance of each other, that doesn't seem to have dampened their willingness to hang out when not on duty. In fact, if Spiridakos' Instagram account is anything to go by, the two seem to be pretty comfortable together when not actually on camera.

For instance, one Instagram post by Spiridakos features a close-up of the two women smiling broadly with the caption, "Happy birthday to the beautiful [Marina]," followed by several birthday-themed emoticons. Another of Spiridakos' posts vouching for their friendly downtime together pictures both women giving a big thumbs-up with the accompanying text: "Burgess lives!" and "New episode of #ChicagoPD tonight."

Yet another indicator of the pair's obvious affection for each other turns up in a segment of a "One Chicago Day" Fan Event interview featuring both women along with Amy Morton, the venerable desk Sergeant Trudy Platt from "Chicago P.D." In a clip from the event posted on YouTube, the two can be seen joking and laughing together as they share anecdotes about their time on the show.

So, despite all their mutual screentime working on the series, there's more than a little evidence that "Chicago P.D." favorites Spiridakos and Squerciati are good friends in real life.