Danish pop/schlager vocal quartet formed in 1956. Original member Otto Brandenburg left in 1958 to pursue a successful solo career and was replaced by Flemming Rasmussen, better known under his stage name James Rasmussen. After the quartet split in 1963 John Mogensen served as a bar pianist for some years before becoming Denmark's most popular schlager artist of the first half of the 1970's.
In 2010 a tribute quartet with singers Keld Heick and Stig Rossen as well as actors Jesper Lohmann and Jesper Asholt started touring as "More Jacks".
