Hot Fuzz/Shaun of the Dead stars Nick Frost and Simon Pegg are trying their hands at a comedy/genre parody sans director Edgar Wright with Paul, which finds the pair playing a couple of hopelessly devoted sci-fi geeks who encounter a legitimate non-Earthling on a road trip across North America.

A full U.S. trailer has been unveiled for the film, which also stars the likes of Kristin Wiig (MacGruber), Sigourney Weaver, Jane Lynch (Glee), and Seth Rogen as the voice of the titular extraterrestrial.

Paul revolves around Clive Collings (Frost) and Graeme Willy (Pegg) – two average British men (and lovers of everything ranging from Star Wars to Stargate) who decide to rent an RV for a road trip that will lead them into America’s UFO heartland. That’s where they encounter the Rogen-voiced Paul, an alien with a raunchy sense of humor who needs to hitch a ride on his mothership before he is caught by a pack of government officials led by Jason Bateman’s Special Agent Lorenzo Zoil (pun intended, of course).

Greg Mottola (Superbad) was at the helm for Paul, which looks to be another fast and fun, adults-only comedy full of nerdy pop-cult references – as well as plenty of lewd jokes about alien anal probes and Paul’s nether regions. The UK trailer released last month featured much of the same footage, though the NSFW jokes that popped up unedited in that preview are only hinted at here.

Watch the U.S. trailer for Paul (via Apple) below:

While Paul himself may be far from a photo-realistic alien creature, he still looks to be a pretty decent CGI creation – who may grind the nerves of moviegoers that are less than affectionate about Rogen’s gruff voice. The movie is likely far more outrageous in tone that this preview might indicate, though the explosive action scenes probably won’t pack the visceral punch as those in Frost & Pegg’s last movie together, Hot Fuzz.

Mottola instilled a surprising amount of heart and sweetness in his previous directorial efforts, the by and large crude coming of age jokefests Superbad and Adventureland – and Paul will hopefully be of a similar design. Having legitimately lovable grown-up nerds like Frost and Pegg as the protagonists should only help matters.

2011 will see no less than nine movies that involve extraterrestrials on Earth hitting theaters around the globe. The invasion kicks off this February with I Am Number Four, then gets really serious with the Black Hawk Down-style action pic Battle: Los Angeles on March 11th. Paul arrives a week later on the 18th and will offer moviegoers a more humorous close encounter of the third kind.