Rihanna reportedly upstaged the bride at a recent wedding by turning up in a boob-exposing dress.

Fellow guests at the nuptials of Rihanna’s cousin Nigel Alstrom's on 27 October were not impressed with the Umbrella pin-up’s stunning blue gown that left little to the imagination – including the fact that she wasn’t wearing any underwear.

Side views of the singer apparently gave conservative wedding guests an eye-full of the star's assets.

One disapproving family member said: "She should have been more low-key, dressed appropriately.

"...she had words with her aunt and mother, and she was asked to leave."

The 19-year-old recently revealed she would never even wear a bikini in a video or photoshoot - because family members would be outraged.