Kaley Cuoco welcomes second baby with fiance who didn't know she starred in the Big Bang Theory

Kaley Cuoco is expanding her brood with fiancé Tom Pelphrey!

The Big Bang Theory actor confirmed the birth of her and Pelphrey's second child, a daughter named Philomena Carmine Bobby Pelphrey, on Instagram yesterday.

Revealing that the youngster had been delivered on Monday (12 October), Cuoco wrote: "There are no words to describe this feeling once again. What a blessing. We are so grateful for the crazy, wild up-and-down journey that brought us to our little Philo!

"Family officially complete. Time to bring Matilda’s baby home!"

Cuoco then went on to praise her Ozark star partner, adding: "Life exploded the minute we met, and the gifts keep coming. I love you forever, girl daddy!"

Philomena is the couple's second chlid together, with the actors previously welcoming their first daughter, Matilda, in March 2023.

Pelphrey also shared his own post dedicated to the newborn, sharing a series of snaps of the couple with infant Philomena alongside the caption: "Another miracle. Welcome to our family, youngest queen!

"Kaley, you showed up in every way as a partner and a mom even when you weren’t feeling your best- you’re a CHAMPION. The girls and I would be lost without you.

"Thank God for the gift of this family and these girls."

Kaley Cuoco and Tom Pelphrey relationship timeline

According to an interview Cuoco gave to USA Today, she and Pelphrey first crossed paths at a premiere event for season four of Ozark in April 2022, with the 40-year-old joking they were 'set up' by their manager.

"It was love at first sight," Cuoco said of the meeting. "We were immediately connected."

The couple went Instagram official a month later, going on to welcome their first daughter the following March.

Cuoco and Pelphrey have spoken publicly about their relationship numerous times, revealing earlier this year that the secret to their relationship success is sleeping in separate bedrooms – a trend which isn't as rare as you'd think.

Separate bedrooms isn't the only surprising fact about the Cuoco/Pelphrey union either, as the 44-year-old previously admitted to never having seen an episode of The Big Bang Theory.

"When I first brought Kaley to New Jersey to meet my family and friends, my mom's partner—who apparently was a Big Bang Theory fan—was there, and he kept calling her Penny," Pelphrey recalled in an interview with W Magazine.

"So I pulled Kaley aside, like, 'I'm sorry, I don't understand what's happening. Why does he keep calling you Penny?' "She's like, 'That's my character in The Big Bang Theory.' I was completely unaware."

Which is certainly surprising, given the show's popularity and the fact that it ran for 12 seasons.