On Tuesday, the "50 First Dates" actress shared a series of before-and-after pictures to her Instagram and also included videos of her intense workouts, all while issuing praise to her trainer, Marnie Alton, for staying on Barrymore throughout her journey.
"This woman is my long time teacher and dear important friend," Barrymore began in the caption. "She has helped me. Healed me. Encouraged me to keep going when I felt like being strong was an insurmountable task."
"We have known each other for about 15 years and when I told her I wanted to transform my body for #SANTACLARITADIET she helped me," she continued, referencing the Netflix series she starred in for three seasons alongside Timothy Olyphant. "Every spring, when I would start training to become #SHEILAHAMMOND Marnie was the one who got me there. I lost 20 pounds and trained like a mother."
The "Charlie's Angels" alum made it a point to mention Alton is a wellness coach for Barrymore.
"We hope the people in the wellness world are actually healthy in their hearts and minds. It's not all about being terminators!" the mom of two said. "It's about how to find yourself. How to be your best self. But we need guidance and we hope our teachers are smart and wise and sane! Marnie is one of the greats. Period. And if your [sic] looking for a life change or to find your consistent tribe, she is where I found mine."
In "Santa Clarita Diet," Barrymore plays the role of a flesh-eating vampire of sorts – a diet that leaves her looking and feeling at her optimum peak. She explained the concept during an appearance on the "Today" show in 2018.
Actors Timothy Olyphant, left, and Drew Barrymore attend Netflix's "Santa Clarita Diet" season 2 premiere at The Dome at Arclight Hollywood on March 22, 2018 in Hollywood, Calif. (Photo by Axelle/Bauer-Griffin/FilmMagic)
"If a woman was really eating just protein and nothing else she would lose weight," said Barrymore.
"It gave me this intense responsibility that I said I want to fulfill to be Sheila and then there was like no excuses," she added of her character.
In December 2018, Barrymore also opened up on social media about her then 25-lb. weight loss and how she adhered to the strict plan Alton set for her from the beginning.
"You can tell my face is so much thinner," she wrote at the time, according to Women's Health. "This takes me so much work. Diet and exercise and fighting like a lion for it! D--n you genetics! And yet thank you for all the good stuff. I love where I come from (JOHN ETHEL LIONEL) and whatever package it comes in. I just know that I have the control to be what I want."