Tyler took to Instagram on Thursday to announce Catelynn had given birth to their daughter on February 21.
"She's here and I'm in love," Tyler captioned a photo of some medical information about the baby.
Tyler and Catelynn's little bundle of joy was born weighing six pounds and four ounces, and she also measured just under 20 inches long.
The baby was born at 9:24AM, and according to Us Weekly, her name is Vaeda Luma.
The newborn joins big sister, four-year-old Novalee Reign, who is reportedly thrilled to have a sibling.
Catelynn and Tyler announced in September 2018 they were expecting their third child together, and the following month, the reality TV stars revealed the sex of their baby.
The middle-school sweethearts placed their eldest daughter, Carly, up for adoption shortly after her birth in 2009 because Catelynn and Tyler were teens and ill-prepared to become parents.
Catelynn and Tyler's marriage seems to be doing well after a month-long separation last year for the sake of their mental health, especially after Catelynn suffered a devastating miscarriage in 2017.
The pair -- who began dating over a decade ago -- reportedly lived in different homes for 30 days, but Catelynn insisted on social media at the time divorce was never an option for them.
Around the time of Christmas, Catelynn and Tyler reunited for a holiday celebration, and they appeared to be closer than ever.
"I love you so much @tylerbaltierramtv thanks for blessing me with three beautiful girls and choosing me as your wife," Catelynn captioned an Instagram photo of the lovebirds holding each other close. "I'm truly blessed by you! I love you!"