She could stash an arrow in there!

In the poster for her upcoming action/comedy Your Highness, usually prim Natalie Portman, 30, shows off her top half in a low-cut shirt.

The flick stars Danny McBride and James Franco as princes on a mission to save their land, and the Black Swan stunner plays an elusive warrior who joins their quest.

And the cleavage-revealing poster is not an isolated occurrence. Stills from the film leaked in December show that Portman, who's currently expecting her first child with fiance Benjamin Millipied, strips down to a thong bikini in one scene.

"I'm not opposed to sexuality or nudity in a film, but I'm very opposed to pornography sites and you're pretty much giving them material if you do any of that," Portman has old V Magazine. "It's always a big dilemma for me."