The news comes about ten months after the pair tied the knot in June 2019.
ET has learned that the couple is expecting their first child together. The news comes about 10 months after the pair married in a gorgeous ceremony in Montecito, California, last June.
A source tells ET, "Chris and Katherine are extremely happy to be pregnant with their first child. The couple knew going into their relationship that having kids together was important to them, so when they found out the news they were extremely happy. Although Katherine was busy promoting her book in the beginning of her pregnancy, she now has time to be at home and get things ready for when the new addition arrives. Chris is so excited."
Schwarzenegger's soon-to-be bundle of joy will be her first child, and Pratt's second. The actor is already dad to 7-year-old son Jack, whom he shares with ex-wife Anna Faris. People was first to report the news.
A source told ET shortly after Pratt and Schwarzenegger tied the knot that they were planning to expand their family.
"The couple is planning to have kids, and doing so is important to them," the source said. "Chris loves children and Katherine comes from a big family and wants the same."
Schwarzenegger, 30, has three siblings -- 28-year-old Christina, 25-year-old Patrick and 22-year-old Christopher -- as well as a half-brother, 22-year-old Joseph Baena. In January 2019, 40-year-old Pratt told ET that he definitely saw having more kids in his future.
"The future? Oh. Lots of kids," he said, adding that he hopes to spend "maybe less time spent working, more time spent enjoying life."
Pratt and Schwarzenegger were first romantically linked in June 2018, and the Jurassic World star announced less than a year later, in January 2019, that he had proposed. See more on the couple in the video below.