Buffy the Vampire Slayer star Nicholas Brendon (Xander) has entered rehab to treat an alcohol addiction. "After realizing that I had a disease that was taking control of my life, I decided that the best way for me to regain my health was to enter a treatment facility," the actor said in a message posted on his website. "I'm grateful for the love and support I've gotten from my wife, Tressa; my entire family; my business associates; and my friends."