Kaley Cuoco and Tom Pelphrey Welcome First Baby Together, Daughter Matilda: 'Little Miracle'

Kaley Cuoco and Tom Pelphrey announced they were expecting in October

Kaley Cuoco and Tom Pelphrey are officially parents!

After the couple welcomed their first child on Thursday, a baby girl named Matilda Carmine Richie, they introduced the "new light of our lives" with some of their first family photos on Instagram.

"Introducing, Matilda Carmine Richie Pelphrey, the new light of our lives!" the new mom wrote. "We are overjoyed and grateful for this little miracle 💓

Tom Pelphrey/Instagram

"Thank you to the doctors, nurses, family and friends who have helped us immensely over the last few days. We are blessed beyond belief 💗 @tommypelphrey didn't think I could fall even more in love with you, but I did 💗," added Cuoco, 37.

Pelphrey, 40, also celebrated the new addition with some sweet photos of the brood, starting the caption with a quote from 13th century Islamic poet Rumi: "You are the Soul of the Universe. And your name is Love."

"My heart is full of love and gratitude for this miracle…. 🤍Matilda Carmine Richie Pelphrey 🤍 3/30," he continued. Eternally grateful for the strength and bravery of my soulmate and best friend @kaleycuoco. You are incredible. 💪♥️"

A source previously told PEOPLE that the mom-to-be, 37, is "very excited about having their baby and ready for the big day."

Cuoco is also secure in her connection with Pelphrey as they prepare to embark on parenthood.

"She is very much in love and gets along great with Tom which makes things even better. She has found her soulmate," added the source.

Cuoco is excited to see the two grow into their new roles as mom and dad, with sources previously telling PEOPLE she believes Pelphrey will be a "hands-on dad."

"Kaley is comfortable about Tom as mate and father, comfortable about the big change the baby will have in their lives, and comfortable about her work," said the source. "They are preparing for the arrival which isn't far off. She is in a good place."

Kaley Cuoco and Tom Pelphrey.

Following the couple's pregnancy announcement in October, Pelphrey told Extra the pair is "so excited" to be welcoming a little girl: "It's the most incredible thing. Very blessed… Very fortunate… Very lucky… Everybody's healthy. It's a beautiful thing."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Cuoco shared a series of photos from her baby shower to her Instagram in January, posting a caption in which she raved about the love she and Pelphrey, 40, were feeling.

"Last night we got to celebrate our future unicorn surrounded by incredible friends, family & animals in the most magical environment," she wrote. "Thank you to the very special group of people who made it a night we will all remember for the rest of our lives."