The 48-year-old actress announced the news to the New York Times, telling the publication that the secret behind her “glowing” skin is pregnancy.
“I’ll be showing soon. Daniel and I are so happy. We’re going to have a little human,” she said.
“We can’t wait to meet him or her. It’s all such a mystery!”
Weisz already has an 11-year-old son, Henry, with movie director Darren Aronofsky, while Craig has a 25-year-old daughter, Ella, from his relationship with Fiona Loudon.
The Academy Award-winning actress started dating the James Bond star in December 2010; the couple married in June 2011 in New York City.
Speaking to ES Magazine about their marriage earlier this year, Weisz revealed: “It’s very personal, it’s very private. I don’t think mine’s particularly exceptional apart from that we’re both in the public eye.”
“I love being Mrs. Craig. I’m Mrs. Craig on my chequebooks and passports and things. I heard about a movie called Mrs. Craig that I want to watch.”