The Five-Year Engagement star, married to Krasinski since 2010, kept her rounder belly covered in her costume for the film, a burgundy dress under a dark blue apron. She was accompanied on set by Billy Magnussen, who plays "Rapunzel's Prince."
Incidentally, Blunt's role in the movie musical is "The Baker's Wife," who desperately wants a child but can't conceive because of a curse placed on her husband's family by "The Witch," played by Meryl Streep. In order to lift the curse, the Baker and the Baker's Wife have to track down four special ingredients the Witch needs for a potion.
In real life, though, the British actress is happily expecting her first child. As the couple's rep first confirmed to Us on Sept. 11, she and Krasinski are set to welcome a tiny bundle of joy in just a few months' time.
"They both want kids, it's one of the reasons they got a bigger place, in a neighborhood that you can raise a family," a source told Us of the couple. "They both couldn't be more excited."
Indeed, Blunt told Manhattan magazine last year that she and her husband were eager to start a family. "We want to have children; I just don't know when yet," she said. "I'm just not sure about the timing of all of that. We're both from big families, so I think it's something we want."