JUSTIN TIMBERLAKE's bachelor bash in Mexico turned cheeky over the weekend (22-23Sep12) when a group of his pals showed their butts to waiting photographers as the star looked on and offered up a partial flash himself.

The pop star-turned-actor headed to Mexico with his friends on Friday (21Sep12) after previously partying in Las Vegas ahead of his upcoming wedding to fiancee Jessica Biel.

Timberlake's antics have attracted a lot of attention, and his pals gave the paparazzi a saucy shot by dropping their trousers and baring their backsides during the trip.

The groom-to-be refused to join in the prank, but did slightly lower his shorts as he smiled at the snappers.