ET spoke to Holt at the premiere of the pair's new Peacock series, 'Based on a True Story.'
Baby to baby!
"I remember seeing her and thinking, 'You're the most glorious pregnant woman of all time, and I don't know how you're working these hours right before you give birth,'" Holt said of Cuoco, who was pregnant with her daughter, Matilda, while filming the Peacock series. "But she's such a pro, and I mean, such an amazing attitude, so, it was very inspiring."
While the pair weren't pregnant at the same time, Holt did find out she was expecting right after filming on the show wrapped.
As for what she's most look forward to when it comes to welcoming baby no. 3 with husband Andrew Joblon, the Australian actress told ET, "It's funny, I had a lot of anxiety with my first two. I was just so nervous about keeping them alive. It's the biggest task and the most precious thing you've ever had, and I feel more confident as a mother now."
She added, "So, I'm excited to enjoy it, and really take it all in this time."
Another thing Holt is excited about is the premiere of the highly anticipated comedy thriller, Based on a True Story. After a serial killer pops up in a California neighborhood a true crime fan (Cuoco) decides to start a podcast about the murders with the help of her partner (Chris Messina), only to be framed for the crimes themselves.
"The caliber of actors is so high. They're unbelievable," Holt gushed. "It's so funny and dark and just everyone loves a serial killer -- not that way. No, we don't -- everyone loves a podcast about a serial killer."
She continued, "So, I think it's just so much fun, and it's such a fun spin on this sort of world, and I'm just really happy to have a small part in it."
Based on a True Story streams June 8 on Peacock.