Tracy Spiridakos

The former Chicago P.D. stars have been traveling the world together lately.

The two Chicago P.D. alums embarked on another unforgettable overseas trip!

Eventually claiming P.D. scene-stealer status, Upton's first day with Intelligence was intense.

Upton and Halstead's wedding day was inspired by a spur-of-the-moment decision, and Chi-Hards gobbled it up.

The actress played Detective Hailey Upton from Seasons 4 through 12 and frequently brought Nala along with her to set.

Chi-Hards will never forget Intelligence Unit O.G. Jay Halstead and his infinite insight.

The Chicago P.D. alumni had an Upstead reunion, and shared a photo from the night with fans.

The Chicago P.D. alum has one of the cutest pets around!

The star may be gone from One Chicago, but she has not been forgotten!

The Chicago P.D. alum could have a future in pet photography!

Chi-Hards everywhere: Upstead is back... kind of.

The former Chicago P.D. star played Detective Haley Upton for eight season before exiting the procedural following Season 11.

Chicago P.D. fan favorite Tracy Spiridakos has been enjoying her Mamma Mia-style travels.

The Chicago P.D. alum chopped off her locks just in time for summer. 

Koteas made a surprise return as Olinsky in Chicago P.D.'s Season 11 finale.

The cop played by Tracy Spiridakos was a force of nature within the 21st District and Chi-Hards adored her.

The series' heart-pumping Season 11 finale was the actress' last episode as Detective Hailey Upton.

The longtime Chicago P.D. star exits the show following the Season 11 finale.

Fans got a pleasant surprise when a certain detective returned for an emotional scene in the Season 11 finale.

These friends and co-stars really knocked this Adele singalong out of the park.