Simon Nicolaas Keizer, born on May 16, 1984, in Volendam, Netherlands, is a Dutch singer-songwriter. He wrote his first song, "Still Searching", in 2000, dedicating it to his deceased father. In 2002, Keizer began collaborating with classmate Nick Schilder, forming the duo Nick & Simon, which operated until 2023. The duo's work included writing songs for and with Jan Smit. In 2008, he contributed to Monique Smit’s debut album Stel je voor, also serving as a backing vocalist for Jan Smit. Keizer released his solo album Ik & Simon in 2016, which included the single "Verdwalen". He later released his second solo album Ruimte in 2025.