Nothing separates Jennifer Aniston [1] from her jeans. There is simply no season or occasion she won't try them on for, as we've learned over the years while tracking her style [2]. From red carpets [3] to date night, Jen has proven that denim isn't just a sign of a casual look.

While she's admitted skinny jeans aren't her favourite and she clearly knows how to rock a slouchy fit, the star's managed to come up with a handful of ideas for every silhouette in the book. Read on for a few of her most trustworthy lessons, some of which come from the '90s, but can still easily be applied today.

Jen Wore Her Boyfriend Cut Jeans With a Bomber Jacket

She Owns Cropped, Straight-Legs That Go Right Down to Her Boots

Jen's Ripped Boyfriend Jeans Balanced Out a Luxe Coat and White Sneakers

Skinny Jeans Lent a Casual Touch to a Sophisticated Blazer

Jen Owns White Jeans, of Course, Which She's Reserved For Summers in the Past

Jen's Olive-Toned Denim Worked With a Handful of Neutrals

She Paired Her With Denim Boyfriend Jeans With a White Shirt and Black Blazer

Boot-Cut Jeans Broke Up a Black Jacket and Brown Boots

Jen Paired These Bootleg Jeans With the Perfect Boot

Slouchy, Rolled Denim Looked Cool With a Jumper and Fedora

She Paired Ripped Boyfriend Jeans With Strappy Heels and a Polka-Dot Blouse

Jen Showed Off Her Functional Brogues by Rolling Up This Pair

Jen Pairs Bell-Bottoms With a White Button-Up Blouse

She Slipped Into Her Light-Wash Crops With Sandals in the Summer

Jen's Worn Booties and Socks With Her Jeans

Jen Made Her Dark Denim Look Like the Perfect All-Black Outfit With Pops of Gold

She Knows They Work Best in Any Silhouette With a White Tee

Jen Always Seems to Wrap a Scarf Around Her Neck When She's in Her Denim

She Once Rolled Up Her Flares to Reveal Converse Sneakers

Jen Used Her Jeans to Play Up a Military Green Anorak and Wide-Brim Hat

Jen Chose a Relaxed Boyfriend Jean on a Rainy Day

For Date Night, Jen Styled Her Belted Flares With Platform Sandals and a Basic Black Vest Top

Jen Wears Her Denim Through Winter With Lots of Layers

She Likes a Proper Look Too — All Belted and Tucked In

In 2009, Jen Exhibited Unexpected Coolness in Some Low-Slung Denim

Jen Made Boot-Cut Dark-Wash Denim Look Sophisticated With a Buttoned Blazer

Jen Pulled off a Parisian Chic Look in 2004 By Wearing Her Jeans With a Beret

Jen Wore a Taupe Wrap Sweater With Her Jeans and Booties

Back in 1998, She Made Mom Jeans Look Fabulous With a Sheer Blouse and Platforms