The Oscar-winner, 36, shared the news on Instagram with a mirror selfie that featured her growing baby bump.
“It’s not for a movie…#2,” she captioned the pic.
Hathaway also hinted that it was a struggle to conceive both her children. “All kidding aside, for everyone going through infertility and conception hell, please know it was not a straight line to either of my pregnancies. Sending you extra love,” she added.
The “Ocean’s 8” star and her husband, Adam Shulman, are already parents to their 3-year-old son Jonathan Rosebanks Shulman. They welcomed him in March 2016.
Hathaway has said motherhood has changed her for the better and she’s “happy when things are simple.”
She told Metro in May 2017, “Since having a kid, I find it a lot easier to do that. The day begins with a checklist: Is he breathing? Is he healthy? Is he growing? Is he thriving? If I get four yeses it’s really hard to upset my day.”
She also revealed to the Sunday Times in February 2019 that she learned a parenting tip from Prince William and Duchess Kate.
“They get down on the child’s level and speak to them eye to eye to make their child feel empowered,” she said. “I thought that was really cool. I started doing that with Jonathan,” Hathaway explained.