Matěj Ruppert, also known as Matthew Ruppert, is a Czech singer performing with the group Monkey Business and an occasional actor.

In elementary school he was a member of the folklore ensemble Rosenka. During his studies at the secondary pedagogical school, he participated in the music competition program "Caruso Show" and won. For four years he worked in the funky band Leguar GR. In 1999 he became the singer of the newly formed group Monkey Business and at the same time was accepted to the conservatory (field of popular singing), but he dropped out after six months. He also played minor roles in several films.