The US actor has been pictured on the cover of Entertainment Weekly in the costume, which is jade-coloured and very futuristic-looking.
He has a white badge on his chest and is wearing one of the famed rings which give each Green Lantern his superpowers.
The new movie - one of many comic book adaptations lately - won't be ready until next year, but it will see Reynolds play Hal Jordan, the first human ever to be selected as a Green Lantern.
He is soon tested when a new enemy emerges and the fate of the universe ends up in his hands.
Back in May, comic fans were urged by the LA Times to keep their eyes peeled for Chris Evans in his Captain America fancy dress costume, as the forthcoming movie is to be partly shot in London.