The 33-year-old actress is believed to be expecting her first child with husband Adam Shulman and friends of the pair say Anne could not be happier.
A source told PEOPLE: "Anne hasn't really slowed down at all," the source notes.
"She was always very active and likes to be out and about. Nothing seems to have changed after she got pregnant. The only difference is that she looks even happier than before. Anne looks great and seems very happy. She seems to have a lot of energy."
Anne and Adam, 34, tied the knot in 2012 and she has previously spoken of her desire to have children.
She said: "I'd like to have as many [children] as I can afford, not just financially but in terms of time, because you want to make sure each one feels special."
"I've had one goal in mind for the past 12 years, which is: get a movie, get a movie, get a movie. Now I might have to say: get a baby, get a baby, get a baby.
"I've wanted to be a mother since I was 16, but I also just knew I wanted to have a career as well. So now I think that I'm getting to an age when I don't know exactly when that moment will be but I think I'm coming upon it."