'Chicago P.D.'s Marina Squerciati and Tracy Spiridakos Delight With Birthday Spa Day Photos

Pictured: (l-r) Marina Squerciati as Kim Burgess, Tracy Spiridakos as Hailey Upton -- (Photo by: Lori Allen/NBC via Getty Images)

Marina Squerciati and Tracy Spiridakos are enjoying some down time away from work.

The Chicago P.D. actresses indulged in a bit of R&R this past weekend in honor of Spiridakos' 36th birthday, which she celebrates on Feb. 20.

In new photos shared by both of the stars of the police procedural series—Squerciati, who plays Kim Burgess, and Spiridakos, who portrays Hailey Upton—via Instagram on Monday, Feb. 19, the duo looked to be having a great time enjoying one another's company, while donning white spa robes.

According to the captions on the social media uploads, the duo enjoyed a staycation girl's trip at The Langham Hotel Chicago's Chuan Spa.

"Serious spa-ing with Tracy! @langhamchicago #staycation #girltriplife #birthdaytrip #birthdaytreat @spiridakos #birthdaygirl," Squerciati's caption read.

Squerciati's snapshot found the ladies in full face masks, from the inside of what looked to be a sauna of sorts, while in the birthday girl's pictures, the pals shot subtle smiles toward the camera after attempting to get a good shot in a couple of silly, blurry ones.

"Spa day with @marinasqu ?????? we had a lovely time, and yes, it took us a minute to sort out the camera angle on this one ?? Thank you @langhamchicago !! ??," Spiridakos noted in her post's caption.

And this isn't the first time the real-life besties have shared their spa experiences with fans. The pair often documents the times they spend together, from taking trips to foreign countries to enjoying down time relaxing, or simply filming at work.

Meanwhile, the two appear alongside one another in the TV series, which airs new episodes on Wednesdays at 10 PM ET on NBC.

Next: 'Chicago PD's Tracy Spiridakos Delights With Shots From 'Beautiful Sunset'