I just tried Lily James’ 600-rep ab workout — here’s what happened

Lily James at 94th Academy Awards and in Pam and Tommy on Hulu
(Image credit: David Livingston/Getty Image and Hulu)

As a fitness editor, there’s nothing I love more than discovering a celeb’s workout secrets, especially when it comes to transformations for a role. I’ve already written about the home workouts Lily James used for her Pam and Tommy transformation, but recently, I’ve seen TikTok explode with another one of James’ workouts — and it involves doing 600 crunches. 

In an interview with Cosmopolitan UK, James said, “We trained five times a week; running, circuits, weights, working out in the gym, and on the track. It was an insane time. When I first had to lift weights, do squats and run for ten minutes I was knackered and wanted to be sick." However, she also said, "I got really obsessed with sit-ups! Whenever the Director shouted 'cut!' I was there on the floor pounding them out. We had to do like 600 different types of sit-ups a day so my stomach changed the most, you just end up looking healthier and stronger”, which seems to be where  TikTok has gotten this challenge from. 

A reminder that what works for James, or me, might not be right for you and your body. 600 reps is an awful lot of any exercise, and if you’re a beginner, you’re new to ab workouts, or you’re returning to exercise after an injury, it’s a good idea to check with a personal trainer to ensure your form is correct before adding hundreds of repetitions to your workout.

What is the Lily James 600-rep ab workout? 

So, it’s not exactly clear whether James actually did 600 sit-ups every day (hey, it worked for David Harbour, who did 1000 crunches a day to prepare for Stranger Things 4), or whether she was exaggerating here, but the TikTok challenge definitely seems to focus on the number 600. Fantastic. 

The silver lining here is that James says “different types of sit-ups”, which makes the challenge ever so slightly more interesting. I did some research into different sit-up variations, unrolled my yoga mat, and gave the challenge a go—read on to find out what happened. 

I just tried Lily James’ 600-rep ab workout — here’s what happened 

After trying Harbour’s 1000 crunches last week, there was no way I was signing myself up for another mind-numbingly boring exercise challenge. In an attempt to make this one more interesting, I settled on six reps of 100 and chose a different sit-up variation each time. Here’s what I went for: 

100 raised leg crunches
100 bicycle crunches
100 swiss ball crunches
100 dead bugs
100 raised leg crunches
100 regular sit-ups 

All of these exercises target the abdominals, but the different variations target slightly different muscles in the core to really feel the burn. It also made it slightly more interesting than just doing endless sit-ups. That said, 50 reps into the 100 raised leg crunches, I realized that 100 reps of any exercise is also an awful lot — serious kudos to Lily James, this challenge is no joke.


BRB trying to look like Pam Anderson. Lily did it in 4 months and i have 10 months so i def can do it

♬ all the time - amelia

I’ve also been slightly sneaky here and left out some of the ab exercises I really hate — V-ups, reverse crunches and Russian twists are all sit-up variations that could be swapped in here, but I’m not that dedicated, sorry team. 

Either way, by the time I got to the dead bugs, my core was on fire, and I was having flashbacks to the tortuous time I did 100 dead bugs a day for a week, (and earned the reputation of ‘dead bug girl’ in the office). After the dead bugs, I stopped and lay on my exercise mat for a good few minutes, watching videos of other people trying the challenge on TikTok to reassure myself I wasn’t alone. 

By the time I got to the regular sit-ups at the end, I was managing 10 reps at a time with short breaks in between. Hats off to Lily James — she worked seriously hard to transform her body in four months. I warn you now, this is a real core burner and it’s not one I’ll be repeating in a hurry. 

If you're looking at other celeb workouts I have tried, you can check out how I tried working out like Nicole Kidman for a week — and here’s what happened. Looking at ab specific workouts? Check out how my colleague tried this dumbbell abs workout that sculpts your core in 15 minutes. You can also read how I did 50 oblique crunches a day for a week — and here's what happened to my abs. I also tried this intense and quick 6-minute ab workout and check out what happened when I tried trainer Krissy Cela's 8 minute ab workout.

Next: I did 30 Good Mornings every day for a week — here’s what happened to my body.

Jane McGuire
Fitness editor

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.