Kilmer's obvious weight loss is drastic. For comparison, check out the actor at the 2011 Comic-Con.
According to TMZ, Kilmer was able to lose the weight the old-fashioned way -- through healthy eating and exercise, "especially long walks on the beach by his home in Malibu."
But perhaps Kilmer is also gearing up for a big Hollywood comeback? The Doors star plays Mark Twain in the upcoming Tom Sawyer & Huckleberry Finn film, and landed a highly coveted role in The Tree of Life director Terrence Malick's still untitled film, due in theaters next year. The secretive Malick film -- about two intersecting love triangles -- also stars A-listers Natalie Portman, Christian Bale, Ryan Gosling and Cate Blanchett.
But Kilmer isn't the only Hollywood actor dropping a significant amount of weight. TheHangover star Zach Galifianakis debuted his own striking weight loss in October, at a screening for his film Birdman Or The Unexpected Virtue Of Ignorance.
Check out the comedian's new look in the video below.