Chrissy Metz Didn't Even Tell Her Real-Life Family About That Major 'This Is Us' Twist

Warning: Spoiler alert! Do not proceed if you have not watched Tuesday's episode of This Is Us. If you have, read our recap and our exclusive postmortem, then come on back...

This week’s This Is Us dropped a massive surprise on fans — but Chrissy Metz, who plays the newly-pregnant Kate Pearson on the show, revealed that not even her own family knew the big twist ahead of time.

Responding to a fan on Twitter who asked, “How hard was that to keep to yourself?” Metz replied: “Beyond difficult! My real family didn’t even have a clue.”

ET caught up with Milo Ventimiglia last month to see what else viewers should watch out for in season two. Check out what he had to say in the video below.

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