I Tried Lululemon’s Trending Define Jacket & I’m Never Taking It Off

The words "hype" and "lululemon" go hand in hand but as familiar as we R29 editors are with the Canadian brand, even we paused when we heard of one of its jackets being heralded as a "BBL jacket" (yes, that BBL). The chatter around the Define Jacket reached our ears via TikTok, where #lululemondefinejacket has over 73 million views. Some TikTokers are claiming the jacket hugs their body so snugly that it accentuates every curve, giving a bum lift effect, while others are praising it for its body "snatching" style.

The lulu girlies always come out in full force to praise the brand's bestselling leggings, bike shorts and trainers, and Team R29 is no stranger to putting these beloved pieces through their paces. We've raved about how well the Align leggings hold up through an intense yoga session, how bouncy and light the Blissfeel trainers feel when running and how useful it is to have pockets in the Fast & Free tights. So when tasked with trying the Define Jacket, £108, I had high hopes. 

I did, however, have reservations about the BBL promise. If this is actually more of a deterrent for you (as it is for me), worry not. Sizing plays a key role in how closely the jacket hugs your figure. The majority of reviews on lululemon's website (which are overwhelmingly positive, btw) recommend taking your usual size. For a real figure-hugging fit, TikTok users suggest sizing down; if you prefer things a little oversized, you can of course always size up. I’m currently between sizes so I went for the latter option, shrugging on a UK size 10 that was snug yet definitely felt like a jacket rather than shapewear.

Lululemon really does operate under the "comfort is key" mindset, as the Define Jacket demonstrates. With added Lycra, the polyester-nylon blend is not only super soft but also seriously stretchy, meaning it moves with your body whether you're running, walking, cycling or just mooching about the house. I’d go as far as to say it feels like a second skin, offering an extra layer of warmth against the incoming autumn breeze while being thin enough to layer under thicker jumpers once the temperature really drops.

Even notoriously itchy elements like the zip, which goes all the way up under the chin, are comfy thanks to padding that folds right around the plastic teeth. The sleeves are long, going right down to your hands, with thumb holes for extra warmth and little flaps that you can fold over your fingers on seriously cold days. Lululemon really has thought of everything. In fact I’m writing this while wearing the jacket indoors on my sofa: a true testament to how cosy and comfy it really is. (Plus I don’t have to drop it to the floor like my trusty dressing gown before every Zoom call.)

Although I swayed away from the super snatched look that has the Define Jacket trending on TikTok, it definitely earned high marks there, too. By sizing up, it was still form-fitting without any sucked-in feeling, which made me feel comfortable and cosy yet not restricted in any way. Detailed seams on the front seemed to accentuate my chest, following the body’s natural curves rather than sitting straight up and down like most other jackets I’ve tried, and the high neck did make my body look longer. (If this isn’t the look you’re after, there's also a cropped style that sits just above the hips.) 

Of course, sizing up didn’t help to achieve a BBL effect, I'm sorry to say. However, as the fabric is so soft, it did follow the shape of my back, which maybe made my bum look a little bit bigger than it would, say, in a fleece. But if I'm being totally honest, this isn’t the reason I’d encourage you to buy this jacket. Comfort is clearly the main attraction.