Brendon, best known for playing Xander Harris on Buffy the Vampire Slayer, began treatment for alcoholism, depression and substance abuse at a facility in California, his rep Andrea Albin wrote in a statement posted to his Facebook page.
"He’s taking the steps necessary to better his health and give himself, and his fans, the gift of a healthy lifestyle," Albin wrote.
Things have apparently been rough for the actor in his personal life as well. In October 2014, Brendon married his girlfriend Moonda Tee in a Las Vegas ceremony. The couple separated and announced their intention to file for divorce in February.
This will also mark the third time Brendon has entered rehab, after undergoing treatment in 2004 and again in 2010.