The couple is expecting their first child, a baby girl.
In one pic, Cuoco joked about Pelphrey's preparedness for parenthood. "Already in dad mode carrying a ton of s**t lol," Cuoco wrote alongside a pic of her bogged-down beau.
The Flight Attendant star also posed for a pic with 40-year-old Pelphrey, in which she stuck her tongue out and he smiled for the camera. "Parents," she captioned the pic.
Other shots show the parents-to-be lounging by the pool with Cuoco's bump on full display.
"It's a crazy time for them but they're truly so excited," a source told ET at the time. "Kaley knows this is the right person. She can't wait to become a mother. They've had so much love and support since the announcement."