RIHANNA wore an eye-popping frock at the Grammys last night that looked like she'd skipped on the undies.

Her floor-length gown had cheeky gaps from neck to toe, with flesh peeping through and no hint of a bra or knickers.

The revealing dress, while flattering the singer's flat tum and toned legs, reminded me of cheap Christmas tinsel.

But JUSTIN BIEBER gave the outfit a thumbs up as he posed with a Chesire cat grin next to the flame-haired star.

At least she didn't sport any of the x-rated outfits from her most recent S&M video.

The clip sees her simulating sex with a blow-up doll, while squeezed into skin-coloured latex amongst many other extraordinary looks.