Taking to her newsletter, the 30-year-old, announced the arrival of their first child and baby boy.
“Michael and I want to introduce you to someone… Meet Hakavai Hoskin,” she wrote in her newsletter.
“We’ll be in this little newborn bubble for a few weeks but we wanted to pop our heads out for a moment to share the news directly with you.”
The former mining engineer announced she is expecting her first child with husband Michael Hoskin on 60 Minutes earlier this year in June and recently shared a snap of her growing baby bump on social media.
During her interview with the Channel 9 news program, she revealed that she discovered she was expecting a few days before she was due to fly to Mt Everest.
She told Hoskin while he was brushing his teeth. "I just walked in and I left the pregnancy stick there," she said.
Pitt has a huge following online after the charity worker suffered severe burns to more than 60 percent of her body in 2011 while competing in a Racing The Planet Ultramarathon in WA struck by wildfire.
Congratulations to the happy couple!