One Chicago will return to screens on NBC One Chicago will return to screens on Wednesday September 26, but there will be some big changes for fans.
In Chicago Med Dominic Rains has left the series as Dr. Crockett Marcel – it is unclear if he will return for season 10 to wrap up his character's arc – while in PD Tracy Spiridakos left the show as Hailey Upton after six seasons as a series regular.
Meanwhile Chicago Fire saw several series regulars leave across the past season including Alberto Rosende as Blake Gallo, Rome Flynn, who only appeared in six episodes, and Eamonn Walker who had been with the series since its first episodes.
However, there are a slew of new names who will bring brand new character that Chi-hards are sure to fall in love with, so let's take a look at who we can expect…
Chicago Fire:
Jake Lockett, as Firefighter Sam Carver, has been upped to a series regular for season 13.
He first joined the show in season 11, where it was revealed he was in the Academy with Lieutenant Stella Kidd (Miranda Rae Mayo) and that she did not think he was "51 material".
Still, he proved her wrong, and eventually opened up about his past, after finding himself in jail, revealing he had an emotionally-abusive relationship with his brother.
In season 12 he became romantically involved with paramedic Violet Mikami (Hanako Greensmith) but by the end of the season his temper appeared again as he was involved in an altercation with an abusive father while on a call.
He then decided to take a furlough after he confessed his love to Violet and she turned him down.
Romcom king Dermot Mulroney will make his debut in Chicago Fire in the season 13 premiere.
He will play the new Battalion Chief, Dom Pascal after 51 said goodbye to their beloved Battalion Chief Wallace Boden.
Very few details are known about the kind of man Dom is, but it is thought he returns to Chicago after a decade in Miami, and has a leadership style very different to Boden.
His estranged wife Monica will also be a recurring character.
KaDee Strickland has been brought in as a recurring role as Monica Pascal, the new Chief's estranged wife.
KaDee is married to Roswell actor Jason Behr.
Jocelyn Hudon joined the series in season 12 as Lyla Novak, a recurring paramedic who loves to float around the different firehouses.
However, she bonds with Violet and in season 12 reluctantly accepts a full-time role on Ambulance 61.
Chicago PD
Toya Turner, 34, known to audiences for her work on New Amsterdam, will join the PD squad in the season 12 premiere.
She will play patrol officer Kiana Cook, who has been described as someone "who loves the adrenaline of the job and its stakes and doesn’t blink in the face of chaos".
Southland and Animal Kingdom alum Shawn Hatosy was cast in PD for a recurring role as Deputy Chief Charlie Reid, and will bring a "new dynamic" to the team.
"I think he sees a lot of himself in Voight [Sgt. Hank Voight, played by Jason Beghe] and identifies quite a bit with Voight and Voight’s philosophy as a police officer, and they have a really interesting relationship that will evolve as the season goes on,” showrunner Gwen Sigan told TV Insider.
Chicago Med:
Darren Barnet will star as Dr. John Frost, a pediatric resident and emergency doctor who is charming and loves children, and "deeply believes that even a young child should understand what is going on with his body and be involved in those decisions".
But he is also harboring his own secrets that will, inevitably, make their way to the ED.
Parenthood and The Bear star Sarah Ramos was announced a new series regular in August as Dr. Caitlin Lenox.
Dr Lenox is an ED Attending, who Med's new showrunner Allen MacDonald described as someone who is interested in being efficient" rather than making friends.
