It’s a shirt! It’s a dress! It’s a shirtdress? Yes, that’s right, shirts and dresses have come together to create the hottest thing in the casual dress styles this season. Tanks, T-shirts, blouses and men’s button-downs were designers’ muses for the casual dresses of spring ’06. So no, no one forgot to cut off the extra material on that oxford and don’t even try to ask for a discount on that dress because you think someone left off the bottom. It’s supposed to look like that. It’s a shirtdress and it’s one of the chicest styles for spring.

Who doesn’t love wearing their boyfriend’s button-downs? There’s something strangely sexy about a woman in a man’s shirt and that something has inspired the latest spring trend. While some designers have created dresses that aren’t much more than oversized oxfords, others have chosen to change the look with ruffles, buttons, belts and pretty much anything else you can think of.

With just a touch of feminine flair, Marc Jacobs takes a boxy, masculine shirt and transforms it into a wonderful piece of women’s wear. Preserving the oxford’s straight, roomy cut, Jacobs swapped out the buttons for a relaxed ruffle that crosses over the chest to close the dress. An oversized collar plays up the ‘girl in men’s clothing’ motif, but the V-neck, cream color and tousled look created by the ruffle make this dress sweet and sultry.

Stella McCartney pairs her baggy blue button-down with a stretch corset belt. Everything about the shirt, from the fit to the color, says boy. With huge breast pockets and chunky cuffs, a girl could drown in this massive man shirt, but a snug corset laces up to cinch this shirt in at the waist. The feminine corset is a drastic contrast to the decidedly masculine shirt, and its small bow adds the final girly touch.

Ralph Lauren morphs the concept of an oxford shirt into something very lady-like with the Valentina dress. The dress’ blue and white pinstripes, button-down front and oxford collar are clearly derived from the classic shirt, but the A-line shape and puffed short sleeves make this dress anything but masculine. A matching pinstripe belt around the waist completes the feminine silhouette and conceals all but a faint musk of manliness.

There’s no low stress look like a jersey dress. Relaxed, yet still ladylike, the jersey dress is simple and sassy. Slip on these slinky frocks with flip-flops for a cute and casual look, or slide into some stilettos for a style that’s soft and sensual. Stella McCartney stuck with the shirt trend and designed a sleeveless cotton-silk blend dress that is subtle and sophisticated. This short scoop neck tank dress is blousy on top and comes down to hug the upper thigh. Lacking in length, McCartney’s jersey dress may appear to be a bit risqu?e, but its loose fit, simple lines and subdued blue grey color give this dress understated elegance.

Theory’s black belted Danne dress leaves a lot more to the imagination, but is nonetheless seductive. Slightly fitted through the hips and loose on the body, the dress exposes the top of the shoulders with a wide but shallow scoop neck and hits at about mid-thigh. Three-quarter length dolman sleeves enhance the dress’s care-free vibe and the look is wrapped up by a twisted tan rope belt. Theory’s jersey dress delicately dangles off the body for a look that’s soft and conservative.

Jersey dresses are a light and flirty spring look, but when shopping for these blousy beauties, stick with solid colors. Stripes and patterns destroy the simplicity of these dresses and you’ll end up looking more like a hot air balloon than a fashion forward femme fatale.

Whether you slip into a jersey dress or throw a belt around a button-down, shirtdressing makes for a contemporary casual look. Put the culottes in the closet and postpone those polos because this spring, the shirtdress is a sure thing.