Published Friday, 09 May 2014
The band is currently touring South America and stopped off at the Parque Olimpico arena in Rio de Janeiro to perform for thousands of fans on Thursday.
During a break from singing, Styles decided to flash the audience, and he unzipped his jeans and pulled them partly down, displaying the inking on the top of his leg.
It is not yet known if the body art is permanent or temporary.
The crowd went wild before the singer quickly covered himself up again and carried on with the show.