How to add libgdx to an existing project

I have provided an application made in android that has a navigation drawer and has a list of games in it. I need to create another game and put it there. The game to be created by mine should use libGDX, but the original application did not use this library.

Can this be done? If so, how do I add libgdx to the output project. On github I only found how to start a new project using libGDx, not how to add it to the code checkout. thank.