Actor Michael Madsen has died after he was found unresponsive early Thursday at his Malibu home, according to authorities and his representatives.

Madsen died from cardiac arrest, his manager Ron Smith told NBC News. Cardiac arrest occurs when the heart stops functioning. It can lead to death without immediate treatment, according to Mayo Clinic.

Hollywood is mourning the loss of Michael Madsen after the actor and Quentin Tarantino collaborator died of cardiac arrest.