This Is Us' Chrissy Metz Felt 'Ill' While Filming 'Unraveling' of KaToby

'This Is Us' ' Chrissy Metz Felt 'Physically Ill' While Filming the 'Unraveling' of Kate and Toby's Marriage

"This is one of the hardest episodes that I've ever shot," Chrissy Metz said of Tuesday's "The Hill," which she co-wrote

Kelly Wynne

Published on March 22, 2022 01:10PM EDT

Kate and Toby's fate isn't just devastating This Is Us viewers.

Chrissy Metz said filming her character Kate's shift in her relationship to Toby (Chris Sullivan) made her sick on set and warned viewers about the end of KaToby. "We're starting to see the unraveling of their relationship," she said during an appearance on Daily Pop.

Tuesday night's episode will feature Kate visiting Toby in San Francisco, where he's relocated for work. "This is one of the hardest episodes that I've ever shot," Metz said. "There were a couple of scenes where I was like, 'Chris, I'm, like, physically ill.' And I think it was just the beginning of the end, of course of the series, but the beginning of the end of their relationship too."

Sullivan, 41, expanded on the heartbreaking plot too. "It's such an important part of relationships to talk about," he said of the decision to end a marriage. "It doesn't get talked about a lot and it doesn't get handled very delicately a lot, and only [creator] Dan Fogelman and our writing staff can take the end of a marriage and still address it with compassion and love."

The time between Kate and Toby isn't lost. "We spent six years loving each other, so it's a bummer to go out like this. But it's also an honor to address this as well as our writing staff is," Sullivan added.

The end of Kate and Toby's marriage was foreshadowed in This Is Us' season 5 finale when Kate was seen marrying her music school boss Phillip (Chris Geere). "I mean, obviously, you saw that Kate has now remarried to another man in that season finale of last year," Metz told PEOPLE (The TV Show!) "When you get to sort of see how things dissolve and how it unravels, you need to brace yourself because while neither Kate nor Toby are right or wrong, you know, people just sort of grow apart if they don't grow together."

This Is Us airs at 9 p.m. ET Tuesdays on NBC. The final episode of season 6 is scheduled to air on May 24.