Pregnant Anne Hathaway sparked Colossal concern after tripping onset

Anne Hathaway panicked the cast and crew on the set of her new monster movie Colossal after falling on her stomach while pregnant.

The Les Miserables star shot the new sci-fi thriller last year (15), while she was expecting her first child, and she refused to sit out some of the more minor stunt scenes, which put writer/director Nacho Vigalondo and her co-star Jason Sudeikis on high alert.

They had reason to be sensitive about her condition when one shoot didn't quite go to plan - and Anne tripped, stumbled and fell face first.

"There's some fight scenes in the movie - some falls," Anne told People.com at the Toronto International Film Festival in Canada, while promoting the upcoming movie. "There's one fall in the movie where I actually did trip, and it was just kind of that thing where I fell on my stomach.

"The reaction in the movie is genuine, and the crew, everybody around me, everyone freaked out for a second."

Anne's baby was just fine and she admits filming while pregnant was not a big deal and didn't affect her performance much at all. It only required a few small adjustments behind the scenes.

"(We had to) just respect certain limitations about, like... 'I know you want me to hit the bed this hard, but I can't - you're gonna have to add a sound effect'," Anne explains.

And, if anything, being with child helped the actress when it came to emotional scenes.

"It was great because through the emotional scenes, I was just there," she smiled.

Anne and her husband Adam Schulman welcomed their son Jonathan, in March (16).