Get ready for a close encounter of the foul-mouthed kind.

Take a four-foot, pot-smoking green alien, add the mouth of a sailor, sprinkle on a few adult jokes and you have Paul (Seth Rogen).

The comedy-adventure is the story of a cosmic smartass who escapes an Area 51 military base where he has been detained for the last 60 years advising world leaders about his kind. He jumps at the first opportunity he sees — an RV with two British, comic book-savvy tourists who are the perfect candidates to rescue and secretly harbor an alien on the run.

On a road trip across America’s heartland, best friends Graeme Willy (Simon Pegg) and Clive Gollings (Nick Frost) find themselves on a sci-fi dream vacation that will change their lives forever.

Graeme, Clive and Paul are hunted by federal agents, “The Big Guy” (Sigourney Weaver) and an obsessive Bible-hugger (Bill Hader), who is the father of Ruth Buggs (Kristen Wiig), a young woman whom Graeme and Clive kidnap after revealing their secret. Buggs joins the two nerds to help return the Martian to his mothership safely.

Although the plot may be a little predictable, this laugh-out-loud humor is unpredictable, putting a twist on the stereotypical introverted alien character moviegoers are used to.

While most science fiction movies portray aliens as a danger to humans, Paul gives viewers a smart-aleck, fun-loving, down-to-earth — literally — character that sheds a new light on intergalactic beings.

Rogen, who caters to a very humor-specific audience, has the natural smartass delivery that is ideal for the outer space character, and Wiig has the necessary loveliness and beauty to give the film a young woman whose liberation leads her to become an ill-advised potty mouth. Pegg and Frost deliver the same comical characters found in 2004’s Shaun of the Dead and 2007’s Hot Fuzz.

The constant bad language may get a little annoying but is used for innocent humor. The clashing theories of intellectual design and evolution come to a head, which could affect the Bible-belt side of the film’s viewers, and some of the action becomes a bit serious.

Moviegoers will find themselves quoting many of the jokes, which are priceless.