Scarlett Johansson does sexy bedhead at Comic-Con. Photo: Kevin Winter/Getty Images

Can Scarlett Johansson ever look bad?

From Marilyn Monroe-blonde to auburn colored tresses, curly to straight, updos to long and flowing, we have seen this movie star look stunning no matter what her hair looks like.

The 25-year-old actress debuted a new bob haircut this weekend when she appeared on the Marvel Studios' "Captain America: The First Avenger" panel at Comic-Con. Shoulder-length and layered with a slight wave, Johansson fashioned her locks in a carefree, bedhead style that looked hip and sexy.

And sexy is definitely something this star knows a thing or two about.

Back in May, Johansson created a splash with her black catsuit-clad attire and curly red hair in "Iron Man 2". She then went back to her blonde roots to appear on the cover of V Magazine with sexy lingerie shots inside. InStyle also featured her on May's cover, but with ringlet-like curls. And most recently, working as the alluring model for international retailer Mango, Johansson wore a '70s-inspired 'do with long auburn-colored locks.

Out of all these looks, we are perhaps partial to her newest haircut -- which is especially provocative when paired with black crop, tuxedo blazer, black bustier and black slacks all by Dolce & Gabbana.

Want more dish on Johansson? Check what she wore to the 2010 MTV Movie Awards.