How Zac Efron got his rippin new bod for Baywatch

Zac Efron has been working hard to get buff for Baywatch. Photo / Getty

Zac Efron splurged on a feast to celebrate a day off from his intense protein and vegetable diet for the upcoming Baywatch movie.

The 17 Again actor has bulked up to star alongside former wrestler Dwayne "The Rock" Johnson in the movie adaptation of the TV series, and was snapped flexing his muscular body on set.

Zac has now explained the diet he has to follow to stay in such a fit shape to fans on Twitter.

"9 days of absolutely zero carbs & sugar. Only organic grass fed/free range protein and organic leafy greens."

He was given a day off from the regime and he made the most of it by ordering food which has been banned from eating.

He posted a picture showing several dirty plates and trays on a table to show how much he cleared by the end of his feast.

9 days of absolutely zero carbs & sugar. Only organic grass fed/free range protein and organic leafy greens. This lead to...

— Zac Efron (@ZacEfron) March 9, 2016

#Cheatday ! Devoured a steak, 4 side potatoes/veggies, macncheese, 3 desserts, bread/butter, brick o cheese & caviar pic.twitter.com/q9hXSoq4us

— Zac Efron (@ZacEfron) March 9, 2016

Zac has also been showing off his new physique in pictures on his social media pages.

On Tuesday, he shared a snap from the set of himself taking on an extreme obstacle course - without stunt wires.

Months of training for this. Bring it on @therock let's do this ALL DAY baby! #NinjaWarrior #Baywatch #nowiresneeded pic.twitter.com/96crwf0aba

— Zac Efron (@ZacEfron) March 8, 2016

He has been competing against Dwayne in the fitness stakes and they recently went head-to-head in a tyre flipping challenge.

View this post on Instagram

Production for the day has ended, all the extras are going home and the sun's going down. Me and @zacefron refuse to quit in a tire shrugging contest that lasted for hours. Why? Because we're #BAYWATCH, we're bad ass and we're a slightly dysfunctional family. ✔️ On a side discipline note juuuuuust wait til you see the insane shape my boy Efron got in for our movie. Proud of the hard work he put in. That's the way you make a character "Iconic". I still kicked his candy ass though in this contest. #OnSet #TwoMeatheadsActingLike12YearOlds #EpicFunThough #BAYWATCH SUMMER 2017 🌊💪🏾

A post shared by therock (@therock) on Mar 6, 2016 at 11:03am PST

Zac is set to play Matt Brody, a character portrayed by David Charvet in the 90s TV series, while Dwayne replaces David Hasselhoff as Mitch Buchannon.

- WENN