It's the most wonderful time of the year: when Hollywood's cutest couple, Emily Blunt and John Krasinski, engage in some serious Christmastime sabotage with their neighbor, friend, and certified prankster Jimmy Kimmel.

Blunt stopped by Jimmy Kimmel Live! on Monday to promote her latest film Into the Woods, as well as be on hand for when host Jimmy Kimmel revealed the details of their latest, epic holiday prank. Now, Blunt and Krasinski—along with Kimmel and his wife Molly McNearney— have been one-upping each other with some pretty crazy stunts over the past few years, but Christmas 2014 may be impossible to top.

That's because over the course of a few days, Blunt and Krasinski have gift-wrapped Kimmel's car, filling it with various items, including tree baubles and even holiday carolers. (The latter, as Blunt pointed out, is Kimmel's worst nightmare.) But none of that compared to the couple's final strike, which included some of Kimmel's personal effects and a stunt that the actress described as costing "so much money!"

Watch the entire segment in the video at top, and be thankful this holiday season that you don't live next door to the adorable, albeit mischievous Emily Blunt and John Krasinski (who makes a cameo in a Santa suit).