Of course, the actor doesn't give specific details - but does give MTV a few clues?
Reynolds says the relationship between Hal Jordan and Sinestro will be further explored, and even mentions "war."
"There's such a rich history with this character, so you get really excited about the possibility," said Reynolds. "The inevitable war between Hal and Sinestro is something that will have to be dealt with in the second movie for sure, but there's always subplots and a lot of other interesting things going on that are setting up a possible third film."
Blake Lively was also on hand, who plays Carol Ferris (love interest of Hal Jordan), and even offered up a clue of her own, as she added that the third film could be about the war between Ferris, as a Star Sapphire, and Jordan/Green Lantern.
Check out the video for more:
The Green Lantern movie opens in theaters June 17th, 2011 starring Ryan Reynolds as Hal Jordan, Blake Lively as Carol Ferris, Peter Sarsgaard as Hector Hammond, Mark Strong as Sinestro and Temuera Morrison as Abin Sur.
Head on over to the Cosmic Book News Green Lantern Movie Hub for more news, images and trailers.