Rachel Weisz felt "very dodgy" during the first part of her pregnancy.
The 48-year-old actress - who already has 11-year-old son Henry with former partner Darren Aronofsky - revealed last week she's expecting a baby with her husband Daniel Craig and she's thankful to be "doing good" after a few months of feeling ill.
Speaking on Good Morning America, she said: "Doing pretty good now.
"I was feeling very dodgy for about four months, but now the good bit's kicked in."
The Disobedience star recently revealed both Henry and Daniel's 25-year-old daughter Ella - who he has with actress Fiona Loudon - are "really excited" about the forthcoming new addition to the family.
Academy Award-winning actress Rachel Weisz compares "Disobedience" to "Shape of Water" and spills on what it was like staring alongside Rachel McAdams. https://t.co/V7slGfTlQD pic.twitter.com/u14ZIEcX2k
She said: "We are ready. Very excited."
Asked if their offspring are pleased with the news, she added: "Yes, they are they are. They are really excited."
The Mercy star announced that the couple have a "little human" on the way during an interview with the New York Times newspaper, where she revealed: "I'll be showing soon. Daniel and I are so happy. We're going to have a little human. We can't wait to meet him or her. It's all such a mystery."
Rachel started dating the James Bond actor in December 2010 and the loved-up couple tied the knot in New York City in June 2011.
The Bourne Legacy star previously admitted that she and the Spectre actor have made a conscious effort to keep their romance "private".
Of their relationship, she said: "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. "
And the Mummy star had never had an ambition to get married before she met Daniel.
She added: "But I never thought I would get married. It was not an ambition of mine. It was the opposite.
"I couldn't relate to romantic comedies - marriage seems to be the whole point of them. Then it just happened, happily, at a more mature moment."