Twilight star Peter Facinelli's actress girlfriend Jaimie Alexander dared to bare on the red carpet at the Thor: The Dark World premiere on Monday night (04Nov13), choosing to go underwear-free in a revealing Azzaro Couture gown.

The sexy 29 year old, who plays Lady Sif in the Thor sequel, stole the show at the star-studded Hollywood screening wearing a black sheer dress that only just covered her breasts, butt and genitals.

The stunning, figure-hugging gown featured a see-through panel that snaked down her sleek body from her neckline to her ankles - but it left little to the imagination.

Alexander has been dating Facinelli, 40, for just over a year.