"On night one of the lockdown, we had a really romantic night of being together, real sweet with my fiancé," the 38-year-old began to explain. "And then I did what everyone else did. I kind of hunkered down and baked a lot of bread. But I just want to say I think I might have baked too much bread or eaten too much bread. You tell me, Seth," she joked about her expanding stomach.
Slate then stood up to reveal her growing baby bump. "It's different. I feel different," she quipped. "Um, how have the exact last nine months been? They've been real pregnant for me."
"Oh, yeah, that's a lotta carbs," Meyers, 46, joked.
It's been "very nice to have something that is incredibly positive during a time that's hard and sad," Slate said, referring to her pregnancy. "It's nice to have a little secret treasure."
The Big Mouth alum has been enjoying quarantine with her fiancé as they are residing "in a beautiful tiny little seaside town" in Massachusetts. To pass the time in lockdown, Slate's been "doing exactly what she has wanted to do, not having to see anyone or figure out how to gracefully wear pants."
She added: "I haven't worn pants in many moons."
The Parks and Recreations alum announced that Shattuck popped the question last September. "He took me to France and made a picnic and made me feel happy and free and then he asked me to marry him and I screamed YES," Slate explained via her Instagram caption. "I love you @benshattuck_art, you are the kindest and brightest and I am so grateful and here we go and keep going ❤️?❤️."
Slate later paid tribute to her soon to be husband — who is an artist and writer — for his birthday with an adorable selfie of the duo. "Happy Birthday to a kooky MA prince, the man called @benshattuck_art who has his birthday one day after my own and who has made my life extremely good and fun and who is my cosmic twin," she gushed. "You are the most excellent, Ben Shattuck, and so is your mustache. Hubba HUBBBBBBAAAAAAA."
Slate shared another fun-loving post of the couple's activities amid lockdown — which didn't include baking bread. "In our #stayhome quarantine we have set up the @benshattuck_art salon and he's doing a great job. Also we are both in onesies like two large babies," she wrote.
The lovebirds were first spotted together last January. Slate and Shattuck made their red carpet debut last May for a movie premiere and have since shared snaps of themselves traveling, enjoying date nights and spending time together.
The happily engaged star previously was in an on-again, off-again relationship with Chris Evans before they called it quits in 2018.