On-screen, their chemistry was undeniable. As Stella Kidd and Kelly Severide, Miranda Rae Mayo and Taylor Kinney created one of the most beloved power couples in Chicago Fire history. But behind the scenes, their relationship was far more complicated than fans ever knew — and at one point, nearly derailed the show’s entire romantic arc.
Insiders from the Chicago Fire set say that the tension between Kinney and Mayo began to surface during Season 9, around the time their characters were headed toward a major engagement storyline. “They were acting like strangers between takes,” said a longtime crew member. “No joking, no eye contact. Just cold.”
The cause? According to multiple sources, a disagreement over creative direction. Kinney reportedly wanted Severide to remain emotionally closed-off, while Mayo fought for deeper intimacy and more shared screen time. “Miranda wanted Stella to be more than the girlfriend,” one insider revealed. “She wanted her to be the equal.”
As their characters fell deeper in love, real-life communication between the actors broke down. A key scene in Season 9, where Severide confesses he’s afraid of marriage, took three days to film instead of the planned one. “They couldn’t find the rhythm,” the director admitted. “It was like pulling teeth.”
NBC grew concerned. The couple had become a fan-favorite. Merchandise, story arcs, and future plots revolved around them. If the actors’ chemistry faded, the franchise would take a hit.
A behind-closed-doors mediation reportedly occurred — not with a therapist, but with executive producers. “They sat them down like parents with their kids,” one writer joked. “And basically said: this is bigger than either of you.”
Remarkably, it worked.
By the time Season 10 premiered, fans were once again swooning over Kidd and Severide’s passion. But those close to the production say their chemistry on-screen is now carefully choreographed. “They’re professional,” said a camera operator. “But that spark? It’s not coming from real affection anymore.”
The drama didn’t stop there.
When Taylor Kinney took a surprise leave of absence in Season 11, rumors swirled that it was due to burnout — but some speculated that behind-the-scenes stress contributed. Miranda Rae Mayo had been given more plot weight, and for some, the shift in dynamic was uncomfortable.
While NBC kept details vague, one insider confirmed that the break “wasn’t just about rest. There were a lot of complicated emotions.”
To fans, Stella and Severide remain iconic — a couple that’s weathered fires, fights, and fierce loyalty. But behind the scenes, the reality is more fragile. Two brilliant actors carrying the weight of fan expectations, network pressure, and personal differences.
And while Firehouse 51 may always burn with drama, some of its hottest sparks may have come from the tension no one was supposed to see
