In the raunchy new comedy “We’re the Millers,” a drug dealer and a stripper pretending to be his wife head to Mexico, bent on smuggling an RV-load of drugs back into the United States. Hilarious!

But there’s more. The fake couple, played by Jason Sudeikis and Jennifer Aniston, who each have filmed past movies in Atlanta (“Hall Pass” and “Wanderlust”), take with them a low-level street punk played by Emma Roberts and a sweet, lonely kid played by Will Poulter. The idea is to look like a family, to evade scrutiny at the border.

Throw in a blizzard of profanity, gross sight gags, ethnic insensitivity and Aniston in multiple pole-dancing scenes and there you are. Movie magic. If that sounds like your thing, “Millers” opens Wednesday.

We were offered a few minutes with the 20-year-old Poulter, known for past work including his role as Eustace Clarence Scrubb in “The Chronicles of Narnia: The Voyage of the Dawn Treader.” Coming up, he’ll be seen in “The Maze Runner.” For now, he plays one of the few entirely likable characters in “Millers.”

“It’s the most unconventional road trip story about the most unconventional family of all time,” he said. “You’ve got a pot dealer, stripper — a real mishmash of personalities. They become very close indeed. You start to believe they are a legitimate family.”

The movie is rated R “for crude sexual content, pervasive language, drug material and brief graphic nudity,” according to imdb.com, and lives up to that billing with Poulter’s character’s most memorable scene. A CGI tarantula makes its way up his pants leg and sinks its fangs into delicate territory, with horrifying results that the fake sibling played by Roberts naturally captures on her phone’s camera for posting purposes.

The scene required hours of preparatory work by a makeup artist gifted in prosthetics.

“This poor dude called Tony had to apply it,” Poulter said. “Just looking down at it made me feel a little bit ill. I thought, ‘This is going to be interesting.’ ”

In a happier scene, Poulter’s character breaks into song, doing a nice job on TLC’s “Waterfalls.”

“It took me a couple of days (to learn the song). TLC’s ‘Waterfalls’ has an embarrassing number of plays on my iPod,” he said. “I was actually quite honored to be rapping.”

Atlanta native Ed Helms appears in the movie as a smarmy drug kingpin, but the two never connected since Helms’ scenes take place removed from the four drug-smuggling adventurers. Despite that and everything else, Poulter was pleased at the opportunity.

“It’s actually got a sweet undercurrent,” Poulter said of the movie. “I’m just lucky I got the role in this and they trusted me with the part.”