The couple, who welcomed a baby girl in 2014, are expecting their second child, a rep for the couple confirmed to ABC News.
The two stars were wed in Italy in 2010 and four years later, welcomed their daughter Hazel. The proud papa Krasinski made the announcement on Twitter at the time.
"Wanted to let the news out directly. Emily and I are so incredibly happy to welcome our daughter Hazel into the world today! Happy bday!" he wrote.
Wanted to let the news out directly. Emily and I are so incredibly happy to welcome our daughter Hazel into the world today! Happy bday!— John Krasinski (@johnkrasinski) February 16, 2014
Both parents have been busy in their professional and personal lives. Krasinski, 36, was just at Sundance this past weekend promoting his film, "The Hollars," while Blunt, 32, is filming her latest movie, "The Girl on the Train."
Blunt had something else to celebrate last year, as the London native was sworn in as a U.S. citizen. She joked about the situation to Jimmy Kimmel in September.
"The thing that's weird is I do get to keep both my British citizenship and this, but you have to renounce [the Queen]. So, it's kind of typically American -- not to be rude -- but I had to renounce her in the room but I don't actually, technically renounce her. They were like, 'Just say it. You don't have to mean it, but just say it,'" she explained.