Wow! This tattoo is really cool, but we wouldn't expect anything less from this ultra-hip boy bander. 

Do you think you can figure out which TV star/singer has this Day of the Dead-inspired skull tattooed on his upper bicep? Here are a few hints to help you out: he's often seen with his three BFF boy band companions, sometimes people confuse his actual last name with the surname 'Knight,' and he's known for being the most mature member of his singing group... at least in TV land.

Have you figured out whose tattoo this is yet? If you're still stumped, click through below to find out!