Production sources have claimed that Finney will play a Foreign Office official, who may attempt to exert control over M (Judi Dench).
Finney reportedly was present for a recent table read of Bond 23's script alongside co-stars Daniel Craig, Ralph Fiennes and villain Javier Bardem.
A production source told the Daily Mail of Finney's casting: "It was one of those fabulous
'This can't get any better!' moments because Mendes has upped the game by bringing in Bardem and Fiennes - and they've already got Dame Judi Dench. So you think, well, who else can they get to make this any classier?"
An official title for Bond 23 hasn't yet been announced, but several URLs recently registered by Song Pictures point to the name Skyfall.
Director Mendes will reportedly film one of the latest Bond movie's explosive action sequences at Duntrune Castle near Glasgow in February 2012.
> James Bond 23: Bérénice Marlohe confirmed as new Bond girl
> Jeffrey Wright not asked back for Bond 23
Watch the trailer for the previous Bond film Quantum of Solace below: