Seconds of Magnus Carlsen Has it been revealed who helped Magnus Carlsen in preparing and during the World Chess Championship against Karjakin?
So far, following seconds have been revealed (NRK, ChessBase): 


GM Peter Heine Nielsen (no surprise as he was part of team Carlsen in WCC 2014)
GM Laurent Fressinet (also no surprise as he was part of team Carlsen in WCC 2013 and WCC 2014)
GM Maxime Vachier-Lagrave (quite a surprise as he is the current world's nr. 4)
GM Nils Grandelius
GM Jan Gustafsson (the tweet of RadioJan was not a joke)
GM Samuel Shankland (a surprise to many, however it was revealed that he also helped for WCC 2014)


Another surprise is that GM Jon Ludvig Hammer was not part of Carlsen's team for this match, while he was for WCC 2013 and WCC 2014. Instead, he chose to do commentary work for VG and Chess.com.