US actor Nicholas Brendon, renowned for his starring role in the cult TV series Buff the Vampire Slayer, has died aged 54.

Brendon's family confirmed in a statement on social media that he passed in his sleep of natural causes. His family added: He was passionate, sensitive, and endlessly driven to create. Those who truly knew him understood that his art was one of the purest reflections of who he was.

Most people know Nicky for his work as an actor and for the characters he brought to life over the years. In recent years Nicky has found his passion in painting and art.

Brendon played Xander Harris in Buff the Vampire Slayer over seven seasons between 1997 and 2003 - best friend of the titular character played by Sarah Michelle Gellar. A planned reboot of Buffy was cancelled, Gellar announced to fans earlier this month.

The Los Angeles-born actor received three Emmy nominations for his role in Buffy, two for best TV actor and one for best TV supporting actor.

Brendon's twin brother Kelly Donovan Schultz also stood in as his brother's body double in two episodes of Buffy. He starred alongside Alyson Hannigan, who shared a tribute in a post, saying, My Sweet Nicky, thank you for years of laughter, love and Dodgers. I will think of you every time I see a rocking chair. I love you. RIP.

Following Buffy, Brendon appeared in various shows including Criminal Minds, Private Practice, and Kitchen Confidential. His film credits include Psycho Beach Party, Big Gay Love, and Redwood.

Brendon was open about his health struggles, including a heart attack, and underwent two spinal surgeries for cauda equina syndrome, a rare condition affecting movement and bladder/bowel function. He struggled with a stutter and advocated for this cause as a spokesperson for the Stuttering Foundation of America.

The actor also faced challenges with substance addiction and mental health issues. His family emphasized in a statement, While it's no secret that Nicholas had struggles in the past, he was on medications and treatment to manage his diagnosis and he was optimistic about the future at the time of his passing.