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Rihanna was given a saucy birthday treat on Saturday (20Feb10) when porn star Bridget The Midget performed a special lapdance for the R&B singer.

The Umbrella hitmaker celebrated her 22nd birthday in Phoenix, Arizona with a surprise party thrown for her by rumoured new boyfriend Matt Kemp.

Rihanna and her friends later moved on to a local bar in Scottsdale - where the Bajan beauty was singled out by the little dancer, before the adult star began gyrating around the birthday girl's chair, reports TMZ.com.