The couple covers The Hollywood Reporter's Rulebreakers issue and, in a rare joint interview, adorably argue about who made the first move when they met at a restaurant in 2008 while Krasinski was out with Justin Theroux.
"Probably me, I think," Blunt, 35, says.
According to the outlet, Krasinski, 39, playfully takes offense to that and turns away from his wife as if channeling his character, Jim Halpert, on The Office. "Yeah, right," he deadpans.
"I think it was me," she insists.
"No," he argues. "It was me asking for a while and you took some time, and then we finally had a date."
Regardless of who asked out whom, the couple eventually had a pizza date that ended at Kransinski's West Hollywood apartment. The Jack Ryan star hesitates to give more details, causing Blunt to call him "Kras," before saying, "It's so precious, I don't want to talk about it. Is that all right?"
Since then, the couple has built a life together -- they have two kids Hazel, 4, and Violet, 2 -- and careers apart. Their careers did become intertwined, though, when A Quiet Place came along. Kransinski wrote, directed and starred in the flick and had always wanted Blunt to star right alongside him, but had opted not to rock the boat by asking.
"I decided the safest thing to do was just have this experience on my own," Krasinski says. "I didn't want this to be the one job that she was like, 'Listen, I don't know if I love this, but I love you, so I'll do it.'"
Blunt, who had even recommended a friend to play her eventual role, insisted on nabbing the job herself after reading the script on a cross-country flight. "I went sort of gray," she says of her reaction to the script. "I couldn't imagine the thought of letting someone else play the part."
Kransinski was thrilled when Blunt cautiously asked him for the role.
"It was like she was proposing to me," he says. "It was one of the greatest moments in my career. I screamed out, 'Yes!' I'm surprised we didn't emergency land in San Antonio."
"I didn't want it to be like, 'Oh, how adorable. They're working together,'" Blunt says of her fears about taking on the project. "It was the only idea that had come our way that seemed bigger than our marriage. The narrative of our marriage was not going to overwhelm this movie and this amazing opportunity for him as a director, as a filmmaker, as a writer. I knew this was a big swing for him."
In addition to working together, Blunt's A Quiet Place role violated another one of her rules -- time off between projects. Blunt, who typically takes months off between roles, let it slide to star in her husband's film.
"I have a minimum of a five-month rule between projects, other than A Quiet Place," she says. "I broke the rule for him and him alone."
While Krasinski was busy writing A Quiet Place, Blunt was hard at work on Mary Poppins Returns, a role she was nervous to take on.
"Friends of mine, they almost started to well up talking about her and what the film had meant to them, and that's when I was like, 'Oh, f**k. What have I done?'" she admits. "I had no option but to Zen it out, because I'd taken this on."
According to Krasinski, Blunt hit it out of the park with her take on Mary Poppins; so much so that the proud husband even admitted to crying while watching the film. ET recently caught up with Blunt, who reacted to Krasinski's sweet confession. Watch the video below to see what she had to say: