A rep for the actor told Just Jared that the tattoo is a tribal pattern relating to his Hawaiian roots and culture and appears to stretch from his forehead, down the side of his head and to his neck.
"Chief of war coming, baby!' Momoa said referring to the upcoming Apple TV + series that is starring, written and executive produced by Momoa.
The project marks the first time Momoa has written for television.
The star then captioned the post, "Here we go @hawaiianairlines is back we're going to New Zealand Hawaii to Aotearoa Mahalo to my ohana for being there for me yesterday @suluape_keone it was a true honor 20 years in the making."
"So stoked @mananalu.water is on the flight mahalo again @hawaiianairlines help stop single use plastic. Always on the roam @soill Aloha j."
The star's tattoo reveal comes almost two weeks after he shaved part of his head in a video where he urged fans to eliminate single-use plastics from their day-to-day life.
Momoa said in a clip: "Doing it for single-use plastics, I'm tired of using plastic bottles, we gotta stop, plastic forks, all that s***, goes into our land, goes into our ocean."
The Game of Thrones actor said that "just seeing things in our ocean, it's just so sad", and pleaded with fans "to eliminate single-use plastics" in their lives, saying that" plastic bottles are ridiculous".