"Ashtyn loves her baby brother, Koda is the sweetest, most gentle dog big sis ever, and mama and baby are doing well," Brittany continued. "This big boy eats around the clock and is gearing up to be built like Hercules like his daddy 🤪. Thanks for all the love and prayers! We are SO blessed and in love and can’t believe that God has given us another precious gift!"
In addition to the sweet announcement, Brittany shared a collage of photos marking Kasen's arrival, from moments before his birth, to being held in mom and dad's arms and a cute pic of the newborn looking as cozy as effort swaddled in a blanket.
Brittany shared another shot of her and baby Kasen on her Instagram Story, in which she detailed more of the little one's birth, and shared that Kaden is brunette, unlike his blonde dad -- for now.
"Another brunette has been added to the family, we'll see if stays that way," Brittany wrote. "I am breastfeeding exclusively, and so far, it has been the best experience."
Brittany went to share that Ashtyn is already such a "sweet" big sister, and that the whole family is on a high in the wake of Kasen's birth. The now mother of two also revealed that she underwent a C-section -- her second -- but that she is recovering much better this time around.
"Kasen wants to thank all his IG aunties for their prayers, especially the ones who have been here since the beginning when we couldn't even get pregnant," she continued. "What a journey it's been but gosh what a beautifully redemptive one."
In February, Kellan shared a compilation video to announce that baby number two is on the way. The clip featured a shot of a positive pregnancy test, before flashing over to Kellan, who was unknowingly being filmed while looking at his phone.
"I invited him to a calendar event 'Baby #2 due date!!!!'" the text on the screen reads. As soon as the calendar invite popped up on his phone, Kellan exclaimed, "You're pregnant? Oh my gosh! What?"
"I couldn't wait to tell you," Brittany replied through tears, as Kellan hugged her.
The clip next showed footage from a sonogram, before ending by showing Ashtyn rocking a "Big Sister" T-shirt as she posed with her parents.
"2 under 2 in 2022 🙌😍 God is Good! Babies are the Best!" Kellan captioned the post. "Love you forever and always @brittanylynnlutz."
When ET spoke with Kellan in 2020, he opened up about how he had always wanted to be a dad.
"I've always had a father's heart and I come from a separated family. My parents were divorced and so never felt complete really," he said. "I'm really looking forward to teaching my children the stuff that I learned not to do and what to do and I want a big family. I really want to have a bunch of kids."