Daniel Radcliffe's mystery girl has been named.

The 21-year-old actor has been seen with a pretty brunette in recent weeks and it can now be revealed his new romantic interest is 19-year-old Olive Uniacke.

Olive is the step-daughter of David Heyman, the millionaire producer of the 'Harry Potter' movies, in which Daniel plays the titular character.

Her father is Robie Uniacke - a London society figure who was recently romantically linked to actress Rosamund Pike - and her mother is his ex-wife Rose, an interior designer.

It is believed the pair have known each other for years because of his starring role in the wizard film franchise and got closer when Olive worked as a PA on the final instalment 'Harry Potter and the Deathly Hallows: Part II'.

A source told the Daily Mail newspaper: "Olive is a lovely young lady - and she and Dan have been close for a long time.

"She was always in and out of his dressing room during filming and she has always been really protective over him."

And Olive - who was a pupil at the prestigious Gordonstoun school, in Scotland, and at the French Lycee, in Kensington, London where Madonna's daughter Lourdes is a pupil - is said to be a fun-loving young woman.

The source added: "Olive is renowned for holding some of the best house parties. She loves to drink champagne and she chain-smokes Camel cigarettes. She also loves to go nightclubbing."