Rebel Wilson revealed her staggering weight loss after completing a taxing four-day fitness program.
The 36-year-old star took to social media to celebrate her triumph.
"OMG, just finished 4 fantastic days at #TheRanch4.0," she wrote.
"So challenging but very rewarding. Not to mention, I lost 8 pounds from marathon hiking over the 4 days!"
Eight pounds translates to roughly four kilos - meaning she shed approximately one kilo per day.
OMG just finished 4 fantastic days at #TheRanch4.0 ...so challenging but very rewarding! Not to mention I lost 8 pounds from marathon hiking over the 4 days! Thanks to the amazing staff and masseuses (free daily massages are part of the program)!! Feeling great!! @theranchmalibu @fswestlake #TheRanch4.0 #theranchatliveoak
According to its website, The Ranch 4.0 program offers "8 hours per day of rigorous exercise including 4 hours of morning mountain hiking, afternoon exercise classes and stretching, delicious organic vegetarian cuisine, massages and a cooking demonstration."
The Ranch has long been a haven for celebrity fitness freaks, attracting the likes of Mandy Moore, Lea Michele, Selma Blair and Rebel's Pitch Perfect co-star, Brittany Snow.
Loved having you @therealselmablair! ··· Arrived. @theranchmalibu. De stress. Exercise. Eat less. Eat more nutrients. Push yourself. Be present. Hiked 4 miles, yoga and core class. Delicious vegan dinner. 425 calories. Nutrient dense food feeds the body. And a lovely moment to relax in gratitude with a mug of detox tea in the beautiful greenhouse .No coffee here. In bed by 830 #theranch4.0. #fswestlake #theranchatliveoak @thealistofficial ?? @mal.schultz