Jen on her 'Justin-Approved' Stripper Ensemble

Jennifer Aniston, Jason Sudeikis, Emma Roberts and Will Poulter play a faux family that assembles for the ultimate road trip -- to smuggle drugs across the border -- in the hilarious comedy We're the Millers, and Jen is perfectly game to share details with ET about her racy strip-tease moment in the movie -- and how she modeled her various lingerie options for fiance Justin Theroux!

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"It was fun to model that all, be enjoyed," quips Jen of her stripper ensemble that Justin "approved."

Watch the video as Jen and Jason also share a laugh and crack a few jokes about the intense interest in their respective upcoming weddings to Olivia Wilde and Justin -- and their "relay race" to see who gets hitched first!

Related: Jen Aniston -- You Can Undo A Lot Of Things

In theaters August 7, the new comedy from Dodgeball director Rawson Marshall Thurber finds Sudeikis as a small-time tasked with moving a huge shipment of weed into the U.S. from Mexico for an insanely wealthy client (played by Ed Helms). Believing that all-American families get through the border unnoticed by authorities, he recruits his neighbors to pose as the "perfect family" – a cynical stripper (Aniston), a virgin "dork" (Poulter) and a runaway "gutterpunk." Can they hold it together long enough to pull it off?