I would say fake and let me explain why! First because I believe there are people who are wiling to waste their time making fake pictures of celebrities. And then it seems like the brand of the underwear have been removed from the photo and I doub that when you are a celebrity and let people take photos of you in this outfit and this position the only thing you are going to say is:
“Dude that’s a great shot! But make sure to remove the brand if this picture goes online when I am famous one day” 😉
But hey you never know we have seen celebrities doing worst (or better) things than a bad underwear picture! The full shot in the second part of the post.