Yes, the one from episode one of The Better Sister.
In the very first episode of The Better Sister, Jessica Biel’s character walks into the scene in a white, nearly backless dress, and it’s all anyone can talk about. The outfit highlights her sculpted, strong, and toned back in a way that’s elegant without trying too hard. Social media lit up with praise and questions, and now Biel has answered with the goods.
Taking to TikTok, Jessica shared the exact strength workout she’s been doing to train for the role, and yes, it’s all about building functional strength and sculpted definition in the back, glutes, and core. Here’s a breakdown of the full routine she posted, and how it helps shape that now-iconic silhouette.
Jessica Biel’s Full-Body Strength Workout
This workout blends free weights, resistance bands, and bodyweight movements. It’s not just about building muscle, it’s about control, stability, and posture. Each exercise focuses on major posterior chain muscles (the back, glutes, hamstrings), which are key to good posture and a confident stance, especially in backless dresses.
Take 60 seconds of rest between sets and focus on form over speed.
1. Dumbbell Hip Thrust
4 sets, 10 reps
Targets: Glutes, hamstrings, and lower back
This move helps lift and shape the glutes while strengthening the lower back, essential for that upright, confident posture.
2. Dumbbell Romanian Deadlift
4 sets, 10 reps
Targets: Hamstrings, glutes, spinal erectors
A classic for a reason. This helps stretch and strengthen the entire posterior chain while encouraging core engagement.
3. Tempo Swiss Ball Hamstring Curl
3 sets, 10–12 reps
With a 3-second lowering phase
Targets: Hamstrings, glutes, core
Slowing down the movement boosts time under tension, which leads to better muscle activation and more definition.
4. Kettlebell Goblet Step-Through Lunge
3 sets, 6–8 reps each side
Targets: Quads, glutes, core, balance
A great dynamic movement that also challenges stability, perfect for defining the waist and building strength in the hips and thighs.
5. Resistance Band Kickback
2 sets, 10–12 reps each side
Targets: Glute max and medius
This isolates the glutes and adds polish to the shape and tone of the backside.
6. Kettlebell Dead Bug
2 sets, 12 reps
Targets: Core, coordination
A functional core move that supports posture and helps create a firm midsection without crunches.
Jessica Biel’s physique in The Better Sister isn’t just a result of genetics, it’s consistency, smart training, and an emphasis on form and control. Her TikTok workout is refreshingly down-to-earth, with no gimmicks or unnecessary fluff. Just solid, effective strength work. It’s important to note that she went to lengths to explain that her workout isn’t sustainable and that training for the role a job that not everyone can achieve.
But you’re after a strong back, lifted glutes, and a silhouette that looks great from every angle (especially in that kind of dress), this workout is a great place to start.
Bonus: Want to know where to get the backless white dress? It is the Selena twisted open-back crepe gown by Proenza Schouler.
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