Reports claim Justin Bieber’s abs for Calvin Klein photo-shoot was clearly photoshopped. Photo: Calvin Klein

Justin Bieber is angry a website made it look like Calvin Klein pumped up his muscles using Photoshop, and unless he gets an admission, he’s going to court.

Justin’s team fired off a demand letter obtained by TMZ threatening Breatheheavy.com with a defamation case for posting a GIF image showing Justin transformed from being mildly muscled to boasting jacked abs.

Bieber and his representatives say the puny photo is fake, clearly Photoshopped and is damaging to his brand.