Jason Momoa stuns fans as he posts his bare bum online

Jason Mamoa is just ass-skin for trouble by showing his bare tushy on Instagram again.

We can't get to the bottom of why he keeps doing it... Anyway, take a look at his arse below:

The 43-year-old shows off a lavender t-shirt with a pair of flip flops to match.

"We got purple, we got pink, we got lavender, we got black. And check it out. Matches the shoes!"

As he walks away from the camera, the video pans down to show off the flip flops, which match the top.

"Know what I'm saying?" the actor says.

Then, all of a sudden, he spins round and his bottom is almost completely bare due to a traditional garment he is wearing instead of pants.

"It's looking good," he says while striding off into the distance.

Viewers were having a hard time concentrating on the actual video, with one person commenting: "There was a shirt and shoes in this video? Must have missed them."

Another joked: "Okay, purple is my new favorite color."

Someone else added: "Sorry I just blacked out for a moment for some reason. Can you’d start again."

Butt, it just so happens that this isn't the first time his ass has been on show.

Last year, the Aquaman character went back out to sea on a Sunday fishing trip, and it was a successful one after copping some big-ass tuna.

Mamoa was was seemingly fishing in little more than a brown loincloth - sort of like a caveman look - and as the sea breeze rippled across the boat, it conveniently blew this rag up in the air, revealing his bare ass, which got more attention than the actual tuna.

One person commented: "Big Mahalo [thanks] for that loin cloth flapping in the wind!"

Another said: "Umm can we get a little extra footage on Jason's fishing outfit?"

Meanwhile, a third added: "Jason what in that thong thong thong song is going on here?"