It was already known that Whishaw would play a part in SkyFall and it was rumoured that he would portray Q, but it was not yet officially confirmed until today. A screenshot of Ben Whishaw of Q has been released, showing a young, 'geeky' Q with Bond (Daniel Craig) in the background.
Whishaw becomes the fourth actor to play Bond’s quartermaster, affectionately known as Q. The role began with Peter Burton as Major Boothroyd in Dr. No followed by Desmond Llewelyn (in 17 Bond films between 1963-1999), and John Cleese (who appeared as Q’s assistant, R, in The World if not Enough and was later promoted to Q in Die Another Day).
The return of the character Q will mean that it's very likely we'll be able to see some new Bond gadgets and/or vehicles, and possibly the return of the classic scene where Bond visits Q's lab and 'admires' Q's inventions.