The actor has become almost inseparable from a striking brunette in the last few weeks. And the mystery brunette who accompanied Daniel Radcliffe on his 21st birthday trip to Russia has been named. She is Olive Uniacke, the 19-year-old step-daughter of David Heyman, the producer of the Harry Potter films.

“Olive and Dan have known each other for a long time, ever since the Harry Potter films started,” a source reveals. “Olive and Dan were close a few years ago, but the relationship fizzled out then,” a source tells the Daily Mail, “Even so, they have always remained friends. And in the last few months they have grown closer again.“