@chungalexa / Instagram 1 / 6
@chungalexa / Instagram 1 / 6

Alexander Skarsgard may have the muscles, but his girlfriend is just as strong in the wit department!

Alexa Chung poked fun at her beau on Instagram on July 5 as he promoted his just-released film "The Legend of Tarzan."

The actor got in tremendous shape for the film, which Alexa dug in at.

The fashion darling stood next to a poster for the film showing her beefy beau.

"Human. Nature. #tarzan I spent 6 months eating high protein meals 5 times a day and hefty regular workouts to prepare for this Instagram. Unclear what the other guy did," Alexa told her 2.3 million followers.

Her fans loved her sense of humor.

The post was still averaging 5,000 likes an hour more than five hours after she shared the fun image.

For the film, Alexander was required to look exactly the same as Tarzan was described in the original 1912 novel, which required months of training for him to get a naturally honed physique rather than a traditional gym-toned body.

His workouts have become something of legend, just like his character.

Alexander's four-month routine saw him waking at 4:30 in the morning for a three-mile run with a weighted backpack. In the afternoons, he did circuit training and boot camp cardio sessions. He was also able to use his own trainer rather than a studio-assigned fitness expert.

"When you have to see the same person every morning at 4:30 a.m.," he explained, "it's important you get on well with them."

In addition to training, he also watched every single item he ate and drank.

He told Mr Porter that he consumed 7,000 calories a day, which consisted of an awful lot of steak and eggs.

In an interview with USA Today, director David Yates said, "Tarzan needs muscles, but it's more a leaner, longer, more vertical modern man than the square-jawed stereotype we're used to."