A 15-year-old boy photobombed a tourist posing with a costumed character in Times Square — then demanded cash for his presence in the snapshot, police said Monday.

Francis Beck, a 52-year-old tourist from Tennessee, told cops that he was taking a photo with someone dressed as a marijuana leaf on Broadway and West 44th Street around 10 p.m. Sunday when the teen butted into the picture.

The kid then demanded Beck give him a tip, but the tourist refused and began to walk away.

The teen began threatening Beck and lifted his shirt to show a black object that the tourist thought was a gun, police said.

Beck called 911, and cops arrested the teen, whose identity has not been released because he is a minor.

He has been charged with attempted robbery and menacing, authorities said.