Zoe Saldana is back in theaters in glorious Na'vi blue this weekend with a return engagement of 'Avatar.' And at the same time, she's showing exactly what's going on underneath all of that motion capture animation in a new Calvin Klein campaign.

The 'Avatar' and 'Star Trek' beauty gets confessional in three new online videos promoting Calvin Klein Underwear's Fall 2010 campaign, according to a company press release.

"I've got nothing to hide," she says in the ad.

And she's not kidding. The Avon beauty -- who helped write the script for the ads -- 'fesses up to having a great poker face and even a tattoo or two.

She also (surprise, surprise) has an affinity for Calvin Klein Underwear, cooing, "Calvin Klein or nothing at all" as she models the label's new Envy line.