Now that's what I'm talking about!

A photo posted by Hugh Jackman (@thehughjackman) on

Hugh Jackman has sparked concern among fans after he posted a photo of himself on Instagram, in which he seems to have dramatically aged. In the photo, the 47-year-old actor looks gaunt, sporting a full beard, cropped hair and revealing heavy circles under his eyes.

In the image, the Wolverine star appears to be in good spirits giving a thumbs up sign as he poses with a plate of fresh fish on a table in front of him. "Now that's what I'm talking about!" he says in the caption.

However, the apparent change in the actor's appearance didn't go unnoticed with his 7.4 million followers, many of whom noted that the Australian star looked distinctly different compared with selfies taken just two weeks earlier in which he poses with his wife.

While the photo garnered 170,000 likes, some fans expressed their concern over the actor's changed appearance.

"Wow, looks like you've lost loads of weight :(," said one concerned fan. "my hero become old, hope you have good health, love you...." added another.

Other's speculated that Jackman might simply be wearing makeup after shooting scenes from his next movie as the actor reprises his role as Wolverine for a final time in the next instalment of the X-Men franchise, which is slated for release in March, 2017. "I hope that is makeup and even if its not they grow up so fast," one fan wrote.

"That's the old man Logan beard... Looks like the comic come to life!!! I'm really gonna miss your take on wolverine," they wrote.

Fans of the star also jumped to his defence commenting: "People cannot age gracefully anymore before been attacked".

The Aussie actor, who plays the lead role in the Marvel film franchise, recently admitted the "insane diet and training regime" he has to be on before filming begins is "annoying".

"Wolverine is very determined and visceral. It's not just his anger that drives him, although he obviously uses anger to his advantage. I don't get angry while playing him. I get more annoyed in the months leading up to the start of filming and having to go on this insane diet and training regime in order to put on 25lbs and bulk up. You'd be angry too if you were eating 6,000 calories a day and bench-pressing 350lbs."