Ben Feldman and Lauren Ash also dished to ET about trying to get Ferrera's pals, Blake Lively and Ryan Reynolds, on set.
America Ferrera's co-stars know her well.
ET's Leanne Aguilera spoke with Superstore stars Ben Feldman and Lauren Ash at NBC's Television Critics Association press day on Tuesday, where they revealed that they guessed Ferrera was pregnant before she made her big announcement.
"We were on set and randomly she said, 'I want pancakes so bad!' And Ben and Colton [Dunn] were like, 'Uh oh! Somebody's pregnant!' and she was like, 'Shut up! No I'm not!' and she hit Colton," Ash recalled. "In that moment, I just locked eyes with her and and I just knew she was pregnant."
"There's a second act to that story, because later that night, we went to an event, and she was there with her husband, and I, just jokingly being a dummy, was like, 'Hey, Ryan [Piers Williams], America told everybody that you guys are pregnant today.' And America turns to Ryan and goes, 'No, I didn't! I didn't! That was not a thing. I did not do that today!'" Feldman added. "And I was like, 'Oh, she's pregnant. She so desperately doesn't want him to be mad at her.'"
"Colton and I visited her in New York a while back, and she told us at her house, which was cool," he continued. "She couldn't hide it anymore at that point, because she was, like, building a nursery."
"She's also, like, 5'1" and let's be honest, it's starting to come out," Ash joked. "So there you go."
As for how Superstore will handle Ferrera's pregnancy, Ash, who is writing an episode of the series, says she "can't talk too much about" their plans for the storyline.
"All I'll say is I've been in the writers' room for a week and what's miraculous is how little we know what's happening. So, there will be a plan and it will be in my episode, but I can't honestly answer the question," she revealed. "I mean, here's the thing, there are lots of options. There are vests. We have boxes that she can be carrying at all times."
One of the first photos Ferrera posted after announcing her pregnancy on New Year's Eve was with her Sisterhood of the Traveling Pants co-stars, whom Ash already has a plan to get on the Superstore set.
"We've all been trying to be like, 'How do we bring this up? We don't want to seem too thirsty.' And then she'll bring something up about like, 'Oh, Blake [Lively] and her husband, Ryan.' And I'm like, 'Reynolds? I'm familiar,'" she said. "Let's get him into the store, you know what I mean? He's Canadian and I'm Canadian, so it's a thing, you know what I mean?"
"I'm just picturing America and Natalie Portman as dates to the Golden Globes. I was just thinking, 'She has a different life than us,'" Feldman cracked. "I don't go to the Golden Globes with Natalie Portman. I watch them in sweatpants, binge-eating at home."
Superstore airs Thursday at 8 p.m. ET/PT on NBC.