John Hurt
All the way back to 2001, when the first Harry Potter film was released. Harry needed a wand of course, and who better to provide it than John Hurt in the guise of wand-maker Mr Ollivander. Of course, the only wand that would work for Harry was the one that was identical to Voldemort's....Hurt is due to reprise his role in the final two films of the series.
John Cleese
The name was Nick. Nearly Headless Nick to be precise. As played by John Clesse in his only Potter outing, the aristocratic ghost of Sir Nicholas de Mimsy Porpington has been roaming Hogwart since his botched execution over 500 years ago. Leader of the Headless Hunt, Nick has been entertaining guests with recreations of his botched execution for many years.
Zoe Wanamaker
The rules may be indecipherable but someone had to teach Harry and co how to play Quidditch. Step forward Zoe Wanamaker who made HP and the Philosoper's Stone her only outing to date.
Kenneth Branagh
A real bad egg, Gilderoy Lockhart was employed by Hogwart's to teach Defence Against the Dark Arts before it was revealed that he had his own bad intentions. He also had one of the best finales, with his new book 'Who Am I'? being featured in the bookstore window in the closing moments.
Eric Sykes
Many people may have thought the veteran English comic actor was in fact dead (he's 86), but in his early 80s Sykes made a one-off appearance in Harry Potter and the Goblet of Fire as Frank Bryce, the ageing caretaker Harry dreams about who overhears Voldemort's evil plans before being summarily murdered.
Julie Christie
In a blink-or-you'll-miss-it appearance, 60s icon Julie Christie turned up in Harry Potter and the Prisoner of Azkaban as Madame Rosmerta, the owner of the Three Broomsticks pub and described in the original book as a 'curvy sort of woman', whom lots of the boys have a crush on.
Miranda Richardson
Chief reporter for the Daily Prophet and Witch Weekly, inquisitive journalist Rita Skeeter was played by Miranda Richardson in the Goblet of Fire, who is rumoured to reprise her role in the forthcoming series finale.