While this will be Schwarzenegger's second child, it will be the third for Pratt, who shares Jack, 9, with ex-wife Anna Faris.
The couple welcomed their daughter, Lyla, in August 2020. A source told ET at the time: "The couple is so excited for their new addition and have been showered with love from their family and friends."
"Chris was there for the birth and the couple can’t stop taking their eyes off their daughter. Katherine and Chris are doing well and Katherine is enjoying the experience of being a first time mother," the source added.
“Giving birth was such a special moment for Katherine. She was overcome with emotions when she first held her daughter and was so thankful to have Chris there," the source shared. "Everything is new for Katherine and she’s glad Chris is there to help her through everything.”
"It's just such a great experience for me and really exciting as well to be able to see my whole family around my daughter," Schwarzenegger shared. "It's really awesome, and, you know, as I've gotten older, to be able to just see different and new opportunities and really new chapters that are really exciting ... this motherhood chapter has just been truly incredible for me and I've enjoyed every single minute of it and I just absolutely love it."