Danielle Fishel — best known for her role in the ’90s sitcom Boy Meets World and its sequel spin-off Girl Meets World — and her husband Jensen Karp welcomed their first child, a baby boy, on Monday, June 24, they announced on Instagram Monday.

The newborn arrived a month before his due date, they shared, telling PEOPLE exclusively that Adler’s middle name, Lawrence, was chosen in honor of Karp’s father, who died 11 years ago. (Incidentally, it is also the maiden name of Fishel’s Boy Meets World character, Topanga Lawrence Matthews.)

“One week ago today, on 6/24 at 4:52am, Adler Lawrence Karp made his entrance into the world, 4 weeks early,” Fishel, 38, began the caption on her post. “My water broke on 6/20, one day before my work week directing at Raven’s Home ended and my maternity leave began. I was hospitalized that night and put on magnesium sulfate because Adler was only 35 weeks old.”

“Unfortunately, after doing an ultrasound, our amazing OB discovered fluid in his lungs that was not there during our last appointment only 10 days earlier — and thus we entered a nightmare we’ll never forget,” she recalled.

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One week ago today, on 6/24 at 4:52am, Adler Lawrence Karp made his entrance into the world, 4 weeks early. My water broke on 6/20, one day before my work week directing at Raven's Home ended and my maternity leave began. I was hospitalized that night and put on magnesium sulfate because Adler was only 35 weeks old. Unfortunately, after doing an ultrasound, our amazing OB discovered fluid in his lungs that was not there during our last appointment only 10 days earlier - and thus we entered a nightmare we'll never forget. We still don't have Adler home with us because the deeply good doctors and nurses in the NICU are working diligently to find out why the fluid is there and determine the best way to get it out. This has been the most trying week and a half of mine and @jensenkarp's lives but we have gotten through it with the support of our incredible family and friends who have shown up for us in unexpected ways. Jensen and I have also become closer than we ever thought possible and the love between us has grown exponentially as we have leaned on each other during both our highest highs and our lowest lows. We feel helpess and powerless and useless and we wanted so badly to follow our "birth plan," unsurprisingly none of which involved leaving our beautiful baby boy at the hospital for the first weeks of his life. We have also struggled with making this announcement - we are THRILLED Adler is here and we want to shout it from the rooftops but we know posting about his birth and it's complications opens us up to prying eyes - aka paparazzi staked outside our house, following our every move they way they did several times during my pregnancy. We are much too fragile for that right now and I pray wholeheartedly that we can have some space as we navigate these next few weeks. I can't wait to share more details about him with you (he hates having a poopy diaper for even 1 minute, he loves bath time, he has the cutest sneezes I've ever heard) and sing the praises of his NICU care team but I prefer to do that when Adler is in this crib in his nursery at home on a still unknown future date. P.S. the fox will be removed from his crib before he's ever in it. ??????

A post shared by Danielle Fishel Karp (@daniellefishel) on Jul 1, 2019 at 8:57am PDT

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I remember being a kid and first hearing about Noah’s Ark in school. Our teacher explained the “two of each animal” thing and called it “a miracle.” And immediately, I had to ask - “What happened to the other animals?” The teacher was confused. I said I knew that there were thousands of other animals alive - so, what happened to the other animals during the flood? The teacher looked at me weird, never answered and moved on, but it was hard to ignore that I figured out that even miracles can’t always be 100% perfect. And so here is Adler Lawrence Karp. Our miracle. He was born a month early on June 24th at 4:52 AM, days after he surprised us with not only an early birth, but with a shocking ultrasound that has since taken over lives. Despite months of clean bills of health, at the last minute, he developed unexplained fluid in both of his lung cavities. Our ensuing rollercoaster ride of emotion, terror, vulnerability and unadulterated sadness has been one we did not expect. Adler is currently in the care of incredible, thoughtful and outlandishly skilled nurses and doctors, yet we’re still in so much pain not being able to bring him home. But, @daniellefishel is a partner in every sense of the word, picking me up when I’m down, asking the right questions, giving the perfect amount of love during our numerous visits each day - and she’s already the parent I can only hope to be half as good as at some point. She’s been my savior, alongside our family and supportive friends, each willing to help, always asking for an update. Adler is already the center of my universe. He’s adorable. He has so much hair. It’s ridiculous. He looks like if Nosferatu was a newscaster. Or a Goth Marv Albert. And he’s fighting so hard every single day. I KNOW he’ll be out soon, kissing me back, ruining our lives, ready to board our ark. I’ve remembered that miracles still can’t always be perfect, but as soon as he’s feeling better, it’s going to be difficult to convince me that this little guy is anything but. I’ve included a second picture - one of the rare belly laugh moments, and public outings, from the past week when Danielle ordered a “seasonal fruit plate” at a nearby deli.

A post shared by Jensen Karp (@jensenkarp) on Jul 1, 2019 at 8:58am PDT

RELATED: Pregnant Danielle Fishel Shows Off Her Baby Bump in Stunning Maternity Snaps: “28 Weeks!”

“We still don’t have Adler home with us because the deeply good doctors and nurses in the NICU are working diligently to find out why the fluid is there and determine the best way to get it out,” Fishel continued. “This has been the most trying week and a half of mine and @jensenkarp‘s lives but we have gotten through it with the support of our incredible family and friends who have shown up for us in unexpected ways.”

“Jensen and I have also become closer than we ever thought possible and the love between us has grown exponentially as we have leaned on each other during both our highest highs and our lowest lows,” she wrote. “We feel helpless and powerless and useless and we wanted so badly to follow our ‘birth plan,’ unsurprisingly none of which involved leaving our beautiful baby boy at the hospital for the first weeks of his life.”

The actress also revealed she and her husband “struggled with making this announcement” because although they are “THRILLED Adler is here” and want to shout it from the rooftops, they’ve been dealing with “prying eyes — aka paparazzi staked outside our house, following our every move they way they did several times during my pregnancy. We are much too fragile for that right now and I pray wholeheartedly that we can have some space as we navigate these next few weeks.”

“I can’t wait to share more details about him with you (he hates having a poopy diaper for even 1 minute, he loves bath time, he has the cutest sneezes I’ve ever heard) and sing the praises of his NICU care team but I prefer to do that when Adler is in this crib in his nursery at home on a still unknown future date,” Fishel continued, concluding, “P.S. the fox will be removed from his crib before he’s ever in it.”

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Realized too late that I basically was Ace Ventura today. Also *Borat voice* is glowingly beautiful.

A post shared by Jensen Karp (@jensenkarp) on Jun 9, 2019 at 6:13pm PDT

RELATED: Boy Meets Breadsticks! Olive Garden Gets Custom Shoes Made for Danielle Fishel’s Son on the Way

The actress announced her pregnancy in an emotional social-media post in January.

“I’m eating for two. I’m napping with wild abandon. Baby shoes. Baby clothes. (I’m shopping). I’m nesting. I’m reading books. I’m madly in love with my husband,” Fishel captioned a snapshot of three pairs of sneakers: one for herself, one for Karp (an executive producer of Drop the Mic) and one tiny pair for their little guy on the way.

“I cry at commercials. I’m a walking cliché. I’ve got baby apps. I’m confident. I feel inadequate,” she continued. “I’m showing one day and the next I’m not. I’m nervous. I’m excited. He’s due in July. We can’t wait. #BabyKarp2019”

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I'm eating for two. I'm napping with wild abandon. Baby shoes. Baby clothes. (I'm shopping). I'm nesting. I'm reading books. I'm madly in love with my husband. I cry at commercials. I'm a walking cliché. I've got baby apps. I'm confident. I feel inadequate. I'm showing one day and the next I'm not. I'm nervous. I'm excited. He's due in July. We can't wait. #BabyKarp2019

A post shared by Danielle Fishel Karp (@daniellefishel) on Jan 2, 2019 at 8:32am PST

RELATED VIDEO: Boy Meets World Alum Danielle Fishel Is Engaged: “No One Is More Excited Than I Am”

Fishel and Karp, 39, tied the knot in November 2018, which she confirmed in a sweet post.

“Mr. & Mrs. Karp. Established 11/04/2018,” Fishel wrote on Instagram alongside a wedding photo that showed off the delicate lace short sleeves of her wedding gown.

Sharing another photo from the nuptials — taken by B.O.B. Photography — Karp wrote, “Today I married my soulmate. We were surrounded by family and friends and it was the best day of my life.”

He jokingly added, “I also ate 3 donuts after dinner. Unrelated. @daniellefishel, I love you so much and thank you for giving me this smile.”

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Can't believe I called the one on the left a "bump" picture.

A post shared by Danielle Fishel Karp (@daniellefishel) on Jun 17, 2019 at 9:06am PDT

RELATED: Baby Boy on the Way for Boy Meets World Alum Danielle Fishel

Fishel reunited with her former Boy Meets World and Girl Meets World costars Ben Savage, Rider Strong and Will Friedle in early May, when the foursome posed together for a hilarious photo op.

In the adorable picture, Fishel wore a black dress and a denim jacket and cradled her growing baby bump. Surrounding her in coordinating outfits, the three guys all placed their hands on their own bellies.

“Boy Meets Baby Bump(s),” Strong, 39, captioned the cute photo, which was taken during the cast’s appearance at Fan Expo Dallas.

Fishel shared the same image to her Instagram account, quipping in the caption, “Sure this was funny — but only one of us is taking 25 bathroom breaks a day.”