Sure Martin Sheen in Badlands looks like a boss in it. So too does Robert Redford in Little Fauss and Big Halsy. In fact, Redford has made it something of a sartorial staple over the years. For most of us, however, denim-on-denim has long been considered a fashion risk, something that without careful handling could propel us dangerously into the territory of Justin Timberlake circa 2001 American Music Awards. Fortunately we live in an age where many of fashion's most rigid rules have fallen by the wayside, and the ban on double denim is one of them. 

Denim is, after all, the people's fabric—it's just too popular to limit to one single item. "The beauty of denim is that it can transcend all these different styles," says Chris Gibbs, owner of popular Los Angeles clothing store Union. And that ability to transcend is exactly what makes doubling up on it so appealing. But there are still rules to consider. For a bit of expert advice, we turned to Gibbs, as well as three other denim experts—Baldwin founder Matt Baldwin, Self Edge denim store owner Kiya Babzani, and 3x1 founder Scott Morrison—to share their thoughts on the Canadian Tuxedo. From fit to wash to fabric, here's what you need to know entering the brave new world of denim-on-denim.

Clothing, Blue, Collar, Denim, Sleeve, Dress shirt, Trousers, Jeans, Shoulder, Textile, pinterest
Baldwin

The easiest way to do it? Pair new with old. 

I love mixing old and new. I think it's really fresh and timeless at the same time. Like a vintage trucker jacket, and then wearing it with a pair of black jeans.  —Matt Baldwin

The best way to pair to denim pieces together, whether it's a denim shirt and jeans, or a denim jacket and jeans, or even a denim jacket on a denim shirt, is that the level of wear should be different on the items. One thing I wear a lot is a raw denim jacket and a pair of jeans, but my jeans are super worn in. So my denim jacket can be the same fabric, but you would never know because the jeans are two years old and super faded. —Kiya Babzani

I'm a big fan of colored denim this season, and I love it when it's paired back to a vintage-looking denim jacket. —Scott Morrison

Or mix light and dark. 

If you're going to pair denim on denim today, you need to have some contrast, like a lighter colored shirt with a darker colored jean. The Canadian Tuxedo I most remember is the Justin Timberlake version from 15 years ago. It was two shades of the same denim (three if you count the hat), both of which were washed down to a flat, mid-blue indigo shade. The wash was also bad, so that didn't help either, but more than anything there was no contrast, especially when paired with a matching T-shirt. A jean jacket and jeans can work well together, but they need to be different shades. —Scott Morrison

I like the idea of a rinsed blue denim, or even raw denim bottom with a washed, lighter denim jacket. —Chris Gibbs

As long as the denim doesn't look exactly the same, and it doesn't have the same exact wash, then it's totally fine. —Kiya Babzani

Blue, Shirt, Textile, Dress, Fashion accessory, Denim, Hat, Electric blue, Formal wear, Costume accessory, pinterest

But keep in mind how dressy you want to be.

The lighter that you go with jeans, the more casual it is. The darker that you go, the more you can dress it up or down. Shade is such an important thing to consider with denim. —Matt Baldwin

And on the subject of matching denim...

It's not a great idea to pair the same denim together. It just looks odd. If you buy raw denim jeans and a raw denim shirt, it just looks like a wall of navy. —Kiya Babzani

A jean jacket and jeans can work well together, but they need to be different shades.

That said, monochromatic isn't completely out of the question.

I love monochromatic styling. There's a definite thoughtfulness. It gives you this really nice high and low without walking down the street and letting everybody see you coming. You can go to the next level with black on black on black. A black chambray shirt, or a black denim shirt, with a rinsed black jean, and then layer it with a black leather jacket. —Matt Baldwin

The only time I think that works is if you're channeling a 1950's rockabilly look. And you're probably modeling in a photo shoot. —Scott Morrison

Tire, Motorcycle, Wheel, Automotive tire, Automotive design, Land vehicle, Fuel tank, Shoe, Fender, Auto part, pinterest
Getty Images

No matter the color, pay attention to fit.

Fit can't be underestimated anytime you're talking about denim. It's the first thing to focus on, and when you're pairing two pieces of denim together you want to make sure they're both appropriately proportioned. Skinny jeans should pair with a slim fitted shirt. Likewise, you wouldn't want to wear a cropped denim jacket with a low-rise jean. The proportions need to be in tandem. —Scott Morrison

I do think fit is really important. Depending on the look you're going for, you should do the fit for that look. For example, if we're talking about this oversized trend, you don't just go get a jacket two sizes too big. There's a proper cut that needs to happen for that to really look its best. Otherwise you look like a kid wearing their dad's clothes. I would call that the high fashion/streetwear hybrid look. Then there's the traditional look, coming from the denim purists, that's more fitted. Like the trucker jacket that's cropped at the waist and properly fitting jeans that are not too baggy or thin, the rockabilly look. And then there's the rocker or hipster look, which is almost the opposite of the oversized look where it's ever so slightly too small. So each kind of look can do denim in its own way. —Chris Gibbs

And focus on quality, too.

There's two ways to look at denim. "Denim" is more synonymous with workwear and the early days of pioneering and industry, and then there's "jeans," from the early '80s where you started to go to a lot wider loom and more mass produced, more everyday wear. I think within that category there are people who do want to make a statement with the fit they're wearing, but also having a fabric that really stands up to your daily wear and tear. —Matt Baldwin

I would argue, when it comes to denim, Japan is making some of the best out there. You can tell— you can touch it and feel it right away—the difference with something made the old way. Japan has a whole industry making clothes predicated on the way we used to make clothes. As the world in the last ten years came to know and understand Japanese denim, it's revitalized the industry to a certain degree. —Chris Gibbs 

You can tell— you can touch it and feel it right away—the difference with something made the old way.

Fly under the radar with tonal stitching.

It's contrast stitching that really makes something look like denim. Overdyed, or garment-dyed denim jackets without contrast stitching are amazing. It starts out indigo but then it's dyed black, and you can wear that with absolutely anything because it doesn't look like your traditional denim. —Kiya Babzani

One last thing: Feel free to break the rules.

There was a restaurant that started here in Los Angeles called The Gorbals. It's in Brooklyn now, but they had this famous dish that they would do: matzo balls wrapped in bacon. Which is obviously a faux pas, but it's 2016, and that's where we are in our society. I think the same thing is happening in fashion. All the rules are out; they're done, they're gone. We've hit a critical mass in fashion where you can kind of make anything look right. —Chris Gibbs