I think that, as people hve said, it's theoretically possible, but you'd have to go through a fair amount of red tape. You are officially only allowed sixteen credits (four courses, definitely not enough for a major) outside of your school, but I would think that you could talk to your advisor and work around it.
However, the vast majority of my friends who are majoring in theater have little enough free time as it is. I'm always seeing them LEAVING at midnight to go start rehearsal for a scene, and hearing horror stories about the long days at studio. They love it, of course, but it's a ton of work. I don't know that it would be such a good idea to pile another major on top of that, especially journalism, which is fairly work-intensive, as the entire program is designed to produce a portfolio of pieces to help you start out in the professional world. If I were you, I'd aim to go into Tisch not planning to double major, but just see where things lead and if you'd feel comfortable with the extra work. Good luck!
"Why, I make more money than... than... than Calvin Coolidge! PUT TOGETHER!"
~Lina Lamont
My name wasn't, isn't, and will never be Scott.