Miley Cyrus debuted a brand new piece of arm candy with the world last night, but it ain't man-shaped and it's a whole lot more permanent.

Miley showed off a fresh tattoo on her forearm of a coiffed '50s style glamourous mystery woman, adding the caption 'Because i am her favourite & she is mine'.

Cyrus later confirmed that it was in fact her maternal grandmother Loretta Finley, who she affectionately knows as 'Mammie'.

Fingers crossed 'Mammie' isn't a traditionalist and doesn't get the shock of her life now that she's literally a part of her granddaughter's appearance.

Miley had the tattoo done by the famous celebrity tattoo artist Kat Von D, who shared pictures of the inking process online after Miley shared the first images, including Miley lying back and getting inked in what appears to be Dracula's crypt.

And it turns out the tattoo was also a bit of a birthday gift to Miley's Mammie, as Miley tweeted Kat again last night.