‘This Is Us’ Star Chris Sullivan Revealed How This 1 Thing May Be the End of Kate and Toby (And No, It’s Not Gregory)

For two seasons now, This Is Us fans have worried relentlessly over Kate (Chrissy Metz) and Toby’s (Chris Sullivan) relationship — and for good reason. The show’s foreshadowing of their demise doesn’t exactly sit well with viewers who hope the two find their way. Sullivan hinted there could be one thing to break them up for good, but it’s not what you probably think.

Kate and Toby met at a support group for weight

Chris Sullivan and Chrissy Metz
Chrissy Metz as Kate, Chris Sullivan as Toby | Ron Batzdorff/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images

In the pilot episode of This Is Us, Kate and Toby meet at a support group where they each shared their struggles with weight and overeating. Despite Kate’s initial resistance (mostly due to the massive wall she put up to protect herself after her father’s death), Toby’s charm won her over and the two began dating.

Their relationship progressed fast, but not without a few bumps along the way. In the last three seasons and counting, they’ve navigated boundaries, fluctuating self-esteem, and Toby’s well-intentioned grand gestures that only Jack Pearson himself (Milo Ventimiglia) could compete with.

Around the time “Katoby” broke up and got back together, Toby suffered a massive heart attack. Not long after, they became engaged and went on to work through their obstacles.

Although their courtship was atypical, plans for having a child remained within view — until Kate’s weight became part of the conversation again.

With that, and the attempt of In Vitro Fertilization (after Kate has a miscarriage), Toby made a big personal decision to increase their chances of having a baby.

Playing Toby with depression took its toll on Chris Sullivan

Once Kate went all-in on IVF, Toby secretly stopped taking his anti-depressant to up the chances he and Kate became pregnant. Season 3 opened with him flushing the pills down the toilet. This move first put Toby in a withdrawal state, then a deep depression.

In the episode that explored Toby’s origin story, depression was everpresent. It’s something he struggled with on the inside while maintaining the happy-go-lucky personality on the outside.

Sullivan told Good Housekeeping in a March 2019 interview that tapping into Toby’s dark side has been his “greatest challenge yet,” even with the warnings he’d been given by the writers beforehand.

“Getting into the anxiety and depression of the character is hard. It’s a hard place to live as an actor because it’s hard to keep those emotions from drifting into your own well-being,” he said. “It’s involved a lot of self-care and re-cooperating after long stretches of that.”

He further explained how hard it was to settle back into reality once those scenes were finished.

“I just kind of try to leave work at work, and be present in the moment. But it doesn’t always work,” he said, adding this side of Toby is necessary for telling an honest story about a flawed being.

“You know, the first season and a half, I thought he [Toby] was kind of a one-sided character. Always upbeat and positive and all these things,” he said.

“Sure enough, the writers gave us the other side of him. It’s been really helpful to kind of understand both of his sides because everybody has them.”

Kate and Toby’s issues are bigger than weight for this important reason, according to Sullivan

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Baby Jack, doo doo doo doo doo doo. #ThisIsUs

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Season 4 revealed a slimmer, fitter Toby to Kate’s surprise, albeit frustration. Theories have already circulated that Toby’s weight loss mixed with Kate’s renewed overeating and weight gain after the birth of baby Jack, could send the couple into rough waters.

However, it’s something Sullivan mentioned in an interview with The Hollywood Reporter fans should keep an eye on.

“I hope that Toby continues to get healthy for his child, stays on his meds, listens to his doctor and continues to connect with Kate in a more deep and intimate way,” he said. “I hope he continues to be the breath of fresh air that everyone thinks he is.”

Fans have already witnessed Toby’s increasingly lack of connection with Kate, but working out and getting fit in secret is part of a bigger issue: Toby may get off his meds again in the future, especially if he thinks his weight loss and new outlook are good enough to keep him going.

If this happens, he’ll likely spiral just as he did before. And, because of that ominous flash-forward in season 3 that revealed a somber, overweight Toby without Kate, Sullivan’s nonchalant comment may hint at things to come.

Sorry, This Is Us fans, but we’re not sure if Kate and Toby go the distance. And it has nothing to do with their new neighbor, Gregory.