Robert Downey Jr.: Real Iron Men Wear Heels.

Robert Downey Jr. was spotted on the set of Iron Man 2 this Monday wearing a pair of sky-high platform boots. Something about his Studio 54 shoes just didn't scream "Tony Stark" to us, so we asked Hollywood costume designer Katherine Jane Bryant why he might be rocking such pumped-up footwear.

"My first reaction when I saw that picture was, 'oh, it has to be for height,'" said Bryant. The former Emmy nominee is responsible for dressing the dapper Don Draper for TV's Mad Men, and says costume designers have all kinds of tricks up their sleeves when it comes to adding inches to an actor's frame. "I can see on the boots that there's a platform and a heel. And you can use lifts thick insoles in the shoes at the same time. I do all three." (For which celebs she wouldn't say.)

Bryant -- who isn't working on the film -- thinks it's likely that the director, Jon Favreau, needed Downey to wear the platforms to appear taller next to a co-star. After all, most estimates place Downey at a modest 5'9". (Gwyneth Paltrow, who plays his assistant Pepper Potts, has at least a good half-inch on him.)

So, aside from the height-enhancing boots, what's Bryant opinion of Downey's overall look? "It's hard to say, because the shoes are a little distracting from the rest," she laughed, "but I think the pants look amazing. I love the tie, and it looks like he's wearing French cuffs. All very expensive."

Now that sounds more like the Tony Stark we know. (Photo: Splash News)