Chris Hemsworth shows off his insane biceps during workout

Chris Hemsworth. Photo / Instagram

Fact: Chris Hemsworth's arms are huge.

And he's dutifully brought them to our attention again with a beautiful mid-workout photo on Instagram.

The 33-year-old's personal trainer Luke Zocchi took a snap of his celebrity client pumping iron in the gym this week during an intense workout.

In the photo, which shows Hemsworth lifting some massive dumbbells, the veins are popping out of his arms which are about the size of a tree trunk.

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Zocchi told fans to tag a "mate who wants the workout to make their arms look like horses legs".

The trainer has worked with the Aussie actor on several movies and teamed with him again for the filming of the upcoming Avengers flick.

"We probably start about three months prior to shooting. So that's when we do our hard work. So basically, when we're shooting, it's just about maintaining it," he told KIIS 101.1's Matt and Meshel in the Morning earlier this year.

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A post shared by Chris Hemsworth (@chrishemsworth)

He said Hemsworth trains once or twice a day with the focus on "old-school body building" and basically zero cardio.

He says they never train for "over an hour at a time".