According to Damon, Johansson “ate, like, an onion sandwich.”

Damon recalled that Johansson said, “Aw s***!

I literally just had … an onion sandwich.”

Scarlett Johansson and Matt Damon smiling

Despite the onion-y ordeal, Damon insists that Johansson’s breath wasn’t actually bad.

“I had to kiss … Scarlett Johansson can you imagine how horrible that was?”

he joked, playfully adding, “It was hell.”

Scarlett Johansson and Colin Jost on the red carpet

Luckily,Johansson’s real-life hubby and SNL star Colin Jostisn’t bothered by this.

I was like, ‘OK, there you go.

I’m glad someone put it together in one package.'"

Duringtheir interview, Emily Blunt explained that “there’s an etiquette” for “intimate scenes.”

According to her, “You gotta brush your teeth.

Stick some gum on the roof of your mouth, and then we can kiss.”

And, of course no onion sandwiches.