When Kaley Cuoco learned she was pregnant before shooting began on the first season of the dark comedy “Based on a True Story,” her character, Ava — a true-crime aficionado on the trail of a serial killer — was given a quick rewrite and became an expectant mother, too.

Not surprisingly, when Cuoco chafed at the rituals of new motherhood, that wound up in the storyline for Season 2 (out Nov. 21 on Peacock), which finds Ava on the scent of a copycat murderer.

“A lot of this came from my own actual experiences of the first six months of being with my kid and despising some of the Mommy and Me classes,” said Cuoco, who had never worked with a baby on camera. “It was new for Ava, it was new for Kaley.”

She lives in Thousand Oaks, Calif., with her partner, the actor Tom Pelphrey, and their daughter Matilda. Motherhood has required Cuoco to re-evaluate and compartmentalize.

“This is the first time in my whole life that I’ve thought about anyone else but myself when it comes to work,” said Cuoco, who for 12 seasons played Penny on “The Big Bang Theory,” and appeared as Cassie for two on “The Flight Attendant,” earning three Emmy nominations. “You think of it as these kind of mini-moments,” she said of the three months of shooting “Based on a True Story,” during which she saw Matilda mostly on weekends.