The Essex reality star told Now magazine he received the injury while shooting the as-yet-named programme with girlfriend Cara de la Hoyde and their fellow Love Island contestant Zara Holland.
"We've got a programme coming up in January and it's very adventurous – I got a black eye from it!" he declared.
"It's a little bit scary, I got bruised," added Cara.
So far there have been no details revealed about what exactly Nathan, Cara and Zara were filming; but if it's airing in January, as Nathan said, then hopefully we don't have to wait too long to find out.
Zara previously revealed she had landed a new TV appearance on ITV, telling Reveal: "It's really challenging... I'm really excited and it's something totally different. Nobody has seen that side of me.
"Everyone will be glued to the TV. I can't wait but I'm a little bit scared, I can't say because that will give it away, but I'm going to do my best."
Although she didn't confirm it was the same show she'd filmed with Nathan and Cara, she did say it was "really challenging" and she was "scared" which fits with Nathan getting a black eye and Cara being bruised.
Meanwhile, there will be NO Love Island Christmas special this year despite widespread rumours.
It had been claimed by The Sun that producers wanted to reunite the couples for a winter special, but ITV denied the report in a statement to Reveal, saying: "There are no plans for a Love Island Christmas Special but we will soon begin casting ahead of another series of the show which will broadcast in 2017."
Ah well, 2017 isn't that far away. Is it?
Cara and Nathan won the summer 2016 series of Love Island and recently moved in together in Essex.