Chris Hemsworth teased by brother Luke for 'out of proportion' pic

Chris Hemsworth viciously trolled by big brother Luke over 'out of proportion' pic. Photo / Instagram

Even Chris Hemsworth's brother Luke is trolling him over a strange detail in the Thor star's latest Instagram post.

The 37-year-old Thor actor posted an innocent photo with his son and a menagerie this week, pulling his best Blue Steel pout with a rabbit, lizard and budgies gathered around him.

But Hemsworth was quick to point out an odd detail in the photo, poking fun at his bulked-up sibling in the process.

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A post shared by Chris Hemsworth (@chrishemsworth)

"A little side hustle I got goin, pet detective. Just returned these animals to its rightful owner. My son. He's trying to repay with love. I'd prefer cash," Chris captioned the snap.

Luke, 40, weighed in, "Dude your head looks enormously out of proportion!? Maybe lay off the dairy? @chrishemsworth"

He wasn't the only one to notice, with one fan writing, "Is it just me or does this look like a Chris Hemsworth bobble head?"

Another follower savaged the star's 'bobble head' pic. Photo / Getty Images

It's not the first time Luke has publicly sledged his younger brother.

In May, the Hollywood star, who is known for his intense workouts, posted a photo of himself on the set of Thor: Love and Thunder walking hand-in-hand with one of his sons.

It was hard to miss his huge biceps, but his fans couldn't resist pointing out the comparatively small size of his legs.

As fans flooded the post with comments, Luke posted a brutal quip: "Bro?! You've been skipping leg days again?!"

What are big brothers for?

A snap from Luke's 40th birthday bash featuring Liam, dad Craig, Luke, his wife Samantha and Chris. Photo / Supplied

Luke is the oldest Hemsworth brother to Chris and Liam, and is known for his recurring role on the hit HBO series Westworld.

Last year, the actor told news.com.au he came within a whisker of being able to add Han Solo to his acting resume.

"I've definitely auditioned for Solo, Han Solo. I really wanted that," he said.

Luke told news.com.au missing out on the role 'hurt'. Photo / Getty Images

"That one really hurt more than others because I wanted it so much.

"You develop a thick skin fairly quickly because more often than not you're getting turned down."

Luke, who moved from LA to Byron Bay where Chris lives with his family last year, described the audition process as an "alien environment.".

"The nature of auditions is you never get feedback," he said.

"They're usually pretty weird. You're just in a chair. It's really hard.

"Confidence is sometimes … It's bullsh*t. It's a bravado.

"You're pretending, you're just trying to get through a performance that doesn't look like you're sh*tting yourself," he said.