Jessica Biel was in "peak shape" in thriller series The Better Sister

But Jessica insisted the shape she was in for the show is "not maintainable unless you are living the strictest, most rigid lifestyle with your nutrition and fitness".

Speaking in a TikTok video, she said: "I just felt I wanted to share that that peak shape in the show is not maintainable unless you are living the strictest, most rigid lifestyle with your nutrition and fitness, which I cannot do.

"So, I'm currently back on my plan to get a little bit back towards that shape."

After doing a series of exercises in the clip, including Romanian deadlifts, goblet step through lunges, hip thrusts, hamstring curls, and cable med glute kickbacks, Jessica admitted she was feeling fatigued and told how she adjusts her workouts depending on what her body "needs to do".

She said: "I'm tired. My body's not 20 years old anymore, you know?

"So, I'm adjusting my workout to what I need to do."

The Sinner star also admitted building muscle is a "key" part of her workout routine.

She added: "You've got to build muscle. That's a key part of my particular routine. And a ton of flexibility.

"I hope it wasn't totally boring. Thanks for checking it out. Let's get older and stronger together!"

While Jessica has plenty of fans on social media, she also has a huge supporter at home - her husband Justin.

After the actress turned 41 in March 2023, he gushed about her on Instagram: " "Let me tell y'all about this human... she is the most bad***, most graceful, most gorgeous DREAM of a partner I could have ever wished for. And today is her bday! I'm so glad you were born, my love. And, I'm so lucky that you are choosing to do this thing called life with me. Aging like a FINE [wine emoji] !!!! I love you to the moon and back. (sic)"