Los Angeles, California - The Big Band Theory star Kaley Cuoco has become a mother for the first time!

The 37-year-old proudly announced the birth of her daughter on her Instagram account on Saturday.

"Introducing, Matilda Carmine Richie Pelphrey, the new light of our lives!" she shared along with several photos holding her newborn baby. "We are overjoyed and grateful for this little miracle."

The new bundle of joy made her arrival on Thursday.

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"Thank you to the doctors, nurses, family and friends who have helped us so much over the past few days," Cuoco added. "We are blessed beyond measure."

The actor announced she was expecting with her partner, Ozark actor Tom Pelphrey, in October.

"@tommypelphrey didn’t think I could fall even more in love with you , but I did," she wrote.

Pelphrey also took to IG to share a post of his own on Matilda's debut.

"My heart is full of love and gratitude for this miracle ... Eternally grateful for the strength and bravery of my soulmate and best friend @kaleycuoco.You are amazing."

Since announcing her pregnancy, Cuoco has shared photos of the two with her bulging baby bump, including on the red carpet of the Golden Globes.

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"Just waitin," she wrote last week.

Cuoco rose to fame on the series The Big Bang Theory playing beloved waitress Penny. She has been married twice before, and announced her relationship with Pelphrey in May 2022.