Rooney, who stars as music-mad 16-year-old Rae in E4’s teen drama, will play a character named Laura in the opening episode of Series 3, ‘The Empty Hearse’, written by Mark Gatiss.

My Mad Fat Diary will return to E4 for a second series next year.

> Find out all the details on Series 3 so far in our summary.

Are you looking forward to Series 3? Let us know below…

> Buy the Series 1-2 boxset on Amazon.

> Buy the BBC’s official book, Sherlock: The Casebook, on Amazon.

Watch a clip from The Hounds of Baskerville…