Kjetil-Vidar Haraldstad (stage name Frost; born 28 June 1973) is the Norwegian drummer in black metal bands Satyricon and 1349. He was born in Øyer, Oppland.

Frost has previously performed with Gorgoroth, Zyklon-B, Gehenna and Keep Of Kalessin. He originally joined Satyricon temporarily to record the demo The Forest is My Throne, later joining the band full-time. He has a degree in Engineering, having taken a course in Computer Science at the University of Oslo.