Jolie has been showing off her acting skills for decades, so it’s no surprise she’s had at least one project during a pregnancy. She starred in Clint Eastwood’s film “The Changeling”, where she played a mother whose son disappears. Her own pregnancy may have increased the emotion of her intense performance, though she only found out she was pregnant at the tail end of the shooting.
She didn’t even make it public until filming was over, and being so early in development meant she didn’t require any extra cover for her character. Jolie ended up with twins and was fine with it – filming a movie about a character losing a son made her want more children.
Angela Kinsey — The Office
Kinsey played another Angela – Martin – on the American version of "The Office". She had a little life growing inside her while filming season four. The producers thought about having her character get pregnant as well, but decided against it.
Thankfully, it didn't prove too difficult to conceal Kinsey's pregnancy during filming. She's so short compared to most of the other cast members, that filming her from the shoulders-up happened naturally. Plus, the office setting made it easy to stick her behind a desk and call it good. Even the mockumentary testimonials are filmed with the face in the center frame and zoomed in, so really there was little she couldn't do.
Naomi Watts — Eastern Promises
Only a few weeks into filming the David Cronenberg project "Eastern Promises", Naomi Watts discovered that she was pregnant. By the time she found out, she'd already performed a few stunts, such as riding through busy traffic on a motorcycle. Had she known about her brand new baby boy, she probably would have left it to a stunt double.
This turned out to be a funny coincidence for Watts – her character in the film is a midwife, and the actress did extensive research on birthing, pregnancies, and fetal development, only to find out she'd be getting a first-hand experience at the same time.
Marcia Cross — Desperate Housewives
For the show "Desperate Housewives", Marcia Cross played Bree Van de Kamp. During the third season, this actress found herself pregnant, and with twins. Even early in pre-birth development, twins make a bump appear much larger and earlier than a single child. And so, the show piled on the big clothes, dark colors, and big props.
Eventually, her doctor told her she needed bed rest, so the show took a long day filming everything they needed from her in one day. After that, she took a long leave, disappearing from the show for the rest of the season and letting the other characters do their thing.
Helena Bonham Carter — Sweeney Todd
Helena Bonham Carter was married to moody director Tim Burton for over a decade. They not only collaborated on a number of films together, but they also collaborated on a pair of children. Carter discovered she was pregnant with one of those children while the movie "Sweeney Todd" was in pre-production – and Carter was one of the leads.
Burton pushed production forward and put her scenes at the top of the order. With a small first-trimester baby bump, and the Burton-standard moody lighting and dark clothing, the movie didn't have any trouble hiding the pregnancy from viewers. Nobody, not even the Demon Barber of Fleet Street, was any wiser.