The two have been doing some last-minute planning before their bundle of joy is born.
The former Office actor is ecstatic about the new addition to his family and shared his excitement on Twitter.
When a fan wrote, "you're going to be a daddy soon," he replied, "Holy crap I AM??? Aaaaaagh!!! Haha, cannot WAIT!!!" (We mean, does he ever stop being so adorable?!)
Blunt has been keeping up with her hikes through Runyon Canyon throughout the holiday season.
She sported a growing baby bump in a Soul Cycle T-shirt while she walked her pet pooch Finn. She wore a similar workout ensemble just a few weeks ago, too!
The 30-year-old actress gathered with close friends and family and held a star-studded baby shower on Dec. 15. Jennifer Aniston, Kristen Bell and more famous faces celebrated the expecting parents at a private residence in Los Angeles.
The Friends star and her beau were photographed arriving at the bash, carrying gifts wrapped in purple paper with a silvery blue bow. She and fiancé Justin Theroux looked casual in matching black jackets.
Meanwhile, the House of Lies blonde made her way to the fête with a cup of coffee and wore a tan coat, a white dress shirt, brown skinny pants and brown booties.
Earlier this week, Blunt was seen grabbing some items at Bel Bambini with a gal-pal.
The now-blond actress was dressed in a pair of skinny jeans, blue sneakers and a white blouse that carefully covered up her bun in the oven.
And like a true friend, Blunt's retail therapy buddy did all the heavy lifting and carried the shopping bags back to their car.
Krasinski and Blunt first announced that they were expecting a baby in September 2013.
The Devil Wears Prada star told Manhattan magazine in 2012, "We want to have children; I just don't know when yet. 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."
It's only a matter of time before a baby makes three for this happy couple!