Apparently, according to rumors-andthis is what it is, just a rumor at the moment- Marvel Studios might have casted yet another former Doctor Who cast-memeber. After Eccleston (the villain in 2013 "Thor: the dark world" and Karen Gillian (the still un-named female villain of the aforementioned Guardians movie) it looks like that there is a chance that David Tennant may be in too.
According to said rumors, Tennant would voice the character that director James Gunn defined the core of the movie and of the team: Rocket Racoon.
(aka this guy here)
Rocket Raccon's character may seem idiotic, but despite his unusual apprence, it's quite a deep character. In the comic book, he in an hightly artifically evolved racoon, a tactical and enginereeng genious, developed to care care and look after the inmates of the largest asylum of the universe and avoid their escape. According to the rumors, in the movie things could be a little different, as he seems to be a "one raccn army" , lonely and afflicted by the knowledge that he is the only one/last one of his kind (a bit like our dear time lord).
But this is just a rumor, emerged after the London Premiere of Iron Man 3.
Also at that premiere, Mark Ruffalo-playing again Bruce Banner after his exploit in Avengers- stated that he had been asked to record his post-credit scene just few weeks before the releaseof the movie, as the real post-credit scene was supposedto be another one. Which one? Marvel didn't say, and we wonder if we will get to see it in the imminent Iron Man dvd/blu ray - but, since all movies in the Marvel Studios Cinematic Universe are connected (Phil Culson in every movie, Fury in Iron Man 1 and 2, Tony Stark in Hulk, Thor in Iron Man 2, Hawkeye in Thor, Fury and Howard Stark in Captain America, Hulk in Iron MAn 3) and one the art released before Iron Man 3 was the "Space Armor" (and since Iron Man, in the comic books, is part ofthe current incarnation of the Guardians of the Galaxy, as they will be portriated in the movie), well... it was supposed to be Tony, reaching with the space armors, answering to a distress call from the gurdians of the galaxy.
But who knows....