When Tropic Thunder hits theaters this summer - on August 15, to be exact - viewers are in for what looks to be a comedy treat.

There's also in for a surprise.

Check out the photo below. You recognize Ben Stiller, right? And Jack Black, in the background? But who is that famous actor in the middle? (Here's a hint: he's actually white!)

Yes, folks, that's Robert Downey Jr.

In Tropic Thunder, the actor plays Kirk Lazarus, a very serious Oscar-winning actor cast in the most expensive Vietnam War film ever. There's a problem with Lazarus's character, Sgt. Osiris, though: hewas originally written as black.

Therefore, Lazarus decides to dye his skin and play the part authentically. Funny? Yes. Dangerous? That's an understatement.

''If it's done right, it could be the type of role you called Peter Sellers to do 35 years ago,'' Downey told Entertainment Weekly. ''If you don't do it right, we're going to hell.''