The TV presenter and author announced her happy baby news via Twitter on Friday morning (14 March), saying she was thrilled to become a mother.
"I am delighted to tell you that our daughter Belle Elizabeth was born today. Overwhelmed with happiness. We can't wait to get to know her," she said.
Katie has been with boyfriend James for two-and-a-half years.
Speaking to Reveal earlier this year, the inspirational star had said the idea of giving birth didn't bother her, after everything she had been through in the past.
I am delighted to tell you that our daughter Belle Elizabeth was born today! Overwhelmed with happiness. We can't wait to get to know her!— Katie Piper (@KatiePiper_) March 14, 2014
In 2008, Katie was the victim of a vicious acid attack at the hands of an ex boyfriend, which left her needing 200 corrective operations.
"I've been through lots of medical procedures and lots of physical difficulties and now I'm going through physical difficulties with an amazing outcome so it doesn't really bother me," she said.
"I definitely feel my life right now is at a high point compared to the extreme lows definitely. I'm really enjoying what I'm doing as a career, I'm thrilled the foundation is going from strength to strength.
"Personally in my life I'm at a point where I didn't know I'd ever be so it's really amazing. I'm really grateful."
Katie, 30, went on maternity leave on 20 February, after her TV show Bodyshockers wrapped. It had followed her around the UK as she visited people who had regretted modifying their bodies with piercing, inkings and plastic surgery.
And she kept herself busy right up until this morning's birth, looking beautiful in a floral dress while attending a Kiddicare event in Hayes last week, and then tweeting last night about enjoying dinner out in Essex.
Congrats to Katie and James!
Katie's not alone! More stars who have welcomed babies in 2014 below:
Copyright: Rex Features WENN/Matthew Taylor/Daniel Deme/Josiah True/Matthre Taylor/Joe