Matthew Arnold Thiessen (born August 12, 1980) is a Canadian-American singer-songwriter who is best known for his role as one of the three co-founders and lead vocalist of Relient K. He has collaborated with Owl City in his albums multiple times. He also provided vocals on four songs from Ocean Eyes, namely "Tidal Wave", "The Bird and the Worm", "Fireflies", and "Cave In".[1]
Thiessen also has his own side project, Matthew Thiessen and the Earthquakes.