It’s pretty much confirmed that Thanos will eventually show up in Disney/Marvel’s movie universe, and the confirmation that he will be played by Josh Brolin points towards an appearance that we will look forward to. There’s not a lot of information regarding the character’s involvement in the films, but the recently released details of the Guardians of the Galaxy plot reveal the ways in which the Mad Titan will appear on the big screen.
The plot details are a little bit spoilery, so if you don’t want even the slightest tidbit of info spoiled, avert your eyes for a bit:
According to Vulture.com, Thanos will first be appearing in Guardians of the Galaxy as a hologram, communicating with his underlings Nebula and Ronan the Accuser. They also claim that Thanos will then make a personal appearance later in the film, although it was not revealed what he will do when he arrives in the flesh.