Hjörvar Steinn Grétarsson is an Icelandic chess player who holds the title of Grandmaster, the highest rank in chess. He was born on 29 May 1993, in the eastern part of Iceland.

Grétarsson became an International Master (IM) in 2009 and achieved the Grandmaster (GM) title in 2011. He represented Iceland in the Chess Olympiads six times from 2008 to 2018. During his career, he has won numerous tournaments including the Icelandic Chess Championship in 2013 and the Reykjavik Open Chess Tournament in 2014.

Grétarsson studied software engineering and is also an active chess streamer on Twitch under the username “Zibbit”. He got the chance to play against Magnus Carlsen, world champion and widely considered the GOAT in chess, in the Banter Cup quarterfinal where he lost in a very close match.