The vegan star, known for his roles in Butterfly, Krypton, and Peaky Blinders, uploaded a topless photo captioned: "The strongest, heaviest & healthiest I've ever been. All on a plant-based diet. And at 40, more importantly than all that s***e, but as a direct result of it, the happiest."
Scanlan also wrote about his plant-based diet on Instagram last month, describing it as 'a ball ache to navigate, but worth it'.
The celeb has urged people to not eat animals earlier this year, when he teamed up with animal-rights charity, PETA, to make an advocacy video.
'Understanding and compassion'
"I'm convinced that if we eat meat, we're ingesting bad karma, but as a by-product of that, by not eating meat, I'm helping the environment," Scanlan said in the video interview. "It's healthier for me. I know, I believe, I feel stronger than I've ever felt before [...]. More importantly than anything, I feel happy that I'm on this path.
"Social media is forcing us out of our slumber. There's nowhere to f***ing hide now. You have to see it. You have to educate yourself. And I think if you raise awareness, then you allow, inside of yourself, to blossom understanding and compassion, which is what I think is the true essence of what human beings are."