Pray for Toby! As This Is Us fans wait breathlessly for the show's Tuesday, January 10, return to learn whether Kate's on-off boyfriend Toby (Chris Sullivan) pulls through after going into cardiac arrest, series star Mandy Moore (Rebecca) tells Us Weekly that the episode takes an emotional toll.

Moore participated in a Television Critics Association press event on the Universal Studios lot on Friday, January 6, where she was asked to comment on the NBC drama's cliffhanger from the winter finale, which featured Toby flatlining on Christmas Eve and getting rushed to the hospital.

"This show is always gut-wrenching," the actress, 32, tells Us. "Every episode, there’s going to be something gut-wrenching. They really know what they're doing! I can’t [say more] … You’ve waited this long."

On a happier note, Moore gushes about her chemistry with Milo Ventimiglia, who plays Rebecca's late husband, Jack. "We just love each other, and it’s so easy to work with each other," she says about the Gilmore Girls alum. "At this point, 15 episodes in, we have our own language. We challenge each other — we’re comfortable with each other."

The License to Wed star adds, "We really lucked out and enjoy each other, and the chemistry was sort of there from the get-go."

Did she expect the series to be so embraced by fans? Not exactly. "We’re still mind-boggled by it," Moore says of the show's success. "I think people were hungry for this kind of entertainment at this particular juncture. I think people wanted cathartic entertainment — they wanted something that resonated on an emotional level with them. It was appointment television that they could talk about, all the characters, obstacles and challenges, with their friends and family and find a way to relate it back to their life. I think people were just hungry for a show like this."

Tell Us: What do you think will happen to Toby?

This Is Us airs on NBC Tuesdays at 9 p.m. ET. 

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