Chris Hemsworth displays Thor muscle gain in Instagram photo

The actor has played superhero Thor since 2011

Hemsworth was captured by his brother Luke ( Frazer Harrison/Getty Images)

Chris Hemsworth appears to have undergone yet another major weight transformation for a film role.

Hemsworth sent the internet into a frenzy with a photo that seems to show the actor looking extremely muscular compared to just a few months ago.

Hemsworth is believed to be bulking up to reprise his role of Avengers character Thor in the next film, which is expected to be released in 2017. Luke Hemsworth, the elder brother of Chris and Hunger Games actor Liam, posted the picture on Instagram and poked fun at his younger brother with the caption: “Hey @chrishemsworth do you even lift bro?”

 

A photo posted by hemsworthluke (@hemsworthluke) on Jan 19, 2016 at 4:09pm PST

The image starkly contrasts with a picture Hemsworth posted of himself just a mere couple of months ago where he showcased his dramatic weight loss for the film In the Heart of the Sea.

“Just tried a new diet/training program called ‘Lost At Sea’. Wouldn’t recommend it,” the 32-year-old joked while looking as ragged as Tom Hanks circa Castaway, 2000.

In December, Hemsworth told Good Morning America he dropped 33lbs in just four weeks for the role. He described being underfed on 500 calories per day as leading to "a pretty moody existence and inconsistent emotions".

He also told the programme that gaining weight is easier as you just "eat a lot and lift weights", which may explain his most recent rapid body transformation.

However, he was also photographed at the People's Choice Awards at the beginning of January and while he didn't look as thin as in the Heart of the Sea image, he didn't appear quite as bulky as in his brother's image, raising questions over whether Luke's photo was the result of a flattering Instagram filter.

Hemsworth won Favourite Action Movie Actor at the People's Choice Awards on January 6 (Kevin Winter/Getty Images)

Actors gaining and losing significant amounts of weight for film roles is nothing new, Renee Zellweger famously gained and lost weight when preparing for her recurring role as Bridget Jones and then returning to roles in films such as Chicago.

In 2015, Bradley Cooper ate every 55 minutes, consuming a total of 8,000 calories per day to gain over 40lbs for his role in American Sniper. The year before Matthew McConaughey was unrecognisable as he shed three stone to portray Aids patient Ron Woodroof in Dallas Buyers Club, for which he won an Oscar.

However, the health effects of ‘yo-yo dieting’ are often a subject of concern for nutritionists. Last week Variety reported that Christian Bale dropped out of the movie Enzo Ferrari over the health concerns for the amount of weight he would have to gain in a certain amount of time. Bale was another actor whose emaciated frame in The Machinist (2004) shocked viewers after losing 60lbs.