The 25-year-old got the tattoo during her recent trip to New Zealand as part of her Diamonds world tour, by tattooist Inia Taylor at the Moko Ink studio in West Auckland.
A description for the studio on the Moko Ink website reads: 'Moko Ink is the worlds first Maori Tattoo Studio specialising in the contemporary use and creation of traditional Maori and Polynesian Tatu.
'We make one off body art keeping alive the language and traditions that are unique to the art form. All our art is custom designed for each person on a consultation basis.
'The language of Ta Moko is used to design a unique piece of body art expressing aspects that relate to the wearer.'
A short video showing RiRi getting her painful tat done, from her fingernails down to the middle of her forearm, was posted on YouTube yesterday.
In the YouTube clip, the Pour It Up keeps cool for most of the procedure, but as tattooist Inia moves on to her knuckles - hitting the chisel with the mallet to place the pigment into her skin, Rihanna begins to grimace.
At one point, Inia is even seen asking the singer to wipe away the blood from her swollen hand so that he can see what he is doing to continue the design.