And, more importantly, find out who made the guest list for the highly anticipated nuptials.

Chicago Fire and Chicago P.D. have been crossing over characters and storylines for years. But the time has come for the NBC dramas to take things to the next level.

Two of the franchise's most beloved characters will tie the knot in Tuesday's episode of Fire, and The Hollywood Reporter has an exclusive sneak peek at the episode.

No, it's not on-and-off couples Casey (Jesse Spencer) and Dawson (Monica Raymund) or Erin (Sophia) and Halstead (Jesse Lee Soffer), but longtime firefighter Mouch (Christian Stolte) and Sgt. Platt (Amy Morton) who are at the center of the heartwarming nuptials.

Just like with any wedding, their's brings plenty of burning questions: Where is the venue? What is the bride wearing? And, most importantly, which of their co-workers made the guest list? (Spoiler alert: Platt shares a sweet moment with one of her P.D. co-stars that will surely water those tear ducts.)

Watch the exclusive video below to get the 411 on the wedding of the year:

Chicago Fire airs Tuesdays at 10 p.m. ET/PT on NBC.