Actor Nicholas Brendon, best known for his role as Xander Harris on the cult classic Buffy the Vampire Slayer, has died at age 53. His family confirmed the death Friday through a statement on his Instagram page, saying he died peacefully in his sleep.

The WB series, which ran from 1997 to 2003, followed Buffy Summers and her friends as they battled supernatural forces while navigating teenage life. Brendon's Xander became a fan favorite as Buffy's loyal, sarcastic best friend - described in early reviews as a would-be Don Juan with an inflated sense of his own charm.

Brendon reprised the role in animated spinoffs and video games, cementing Xander's place in pop culture. His film debut came in the 2000 camp comedy Psycho Beach Party, where he played Starcat opposite Lauren Ambrose's Chicklet. The actor had been open about his struggles with mental health and substance abuse in recent years.