Northern Kings was a Finnish symphonic metal cover supergroup, made up of four well known musicians: Jarkko Ahola from Teräsbetoni, ex-Dreamtale, Marco Hietala from Nightwish and Tarot, Tony Kakko from Sonata Arctica and Juha-Pekka Leppäluoto from Charon and Harmaja.

Based on the paragraph above can we conclude that "The Nothern Kings's members were famous from being in other groups"?
Yes