Jonas Bak-Andersen is the third child of Kim and Monica Bak-Andersen. He has fraternal twin brother Marius. He was born 27 March 2017. He has older sisters Silje from 2010 and Selma from 2011. He lives with his family in Lyngby, Copenhagen.
Jonas was born at Herlev Hospital, Copenhagen on 27 March 2016 at 11:27. They were born by emergency c-section at 37+2. They are being watched at home by their mother in the house in Lyngby.