The 22-year-old reality star gave birth to daughter Nova Reign on New Year's Day and is clearly already besotted with the tiny tot.
Alongside a sweet picture of Nova's teeny tiny feet on Instagram, she said: "You are already my world. I love you so much. You have already changed me in so many ways."
Catelynn and long-time boyfriend Tyler Baltierra rose to fame on MTV reality shows 16 and Pregnant and Teen Mom, which documented Catelynn's pregnancy at the age of 16 and the couple's decision to place their firstborn daughter Carly up for adoption as they felt it was in her best interests.
Their happy baby news has been somewhat marred by nasty comments online about Carly, prompting a frustrated Tyler to tweet in response: "So sick of the ignorance in the world. Just because you place a child for adoption doesn't mean your not allowed to have another #GetReal."
Tyler, 22, had told Twitter followers he'd been thinking about Carly while Catelynn was in labour with Nova, posting a throwback picture of himself cradling a newborn.
He also told fans he was "crying happy tears" as this time he was bringing his child home.
"Having her here feels unreal but actually taking her home feels even more unreal," he said. "I actually get to be happy about leaving the hospital… Crying happy tears instead of sad ones feels AMAZING! I don't have to be heartbroken this time."
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