Alex started his career with KR Reykjavik in his home country. He went on to join FC Nordsjaelland in Denmark, where he made 62 appearances during a three-year spell, before moving to Dijon.
Technical director Edu said: “We’re very pleased to welcome Alex to our squad. We have been monitoring him for some time and from the analysis, he has strong attributes that we look for in a goalkeeper and as a person.”
Mikel Arteta added: “We want to create healthy competition for places and we look forward to seeing Alex bring further depth to the goalkeeping position.”
Alex will wear the number 13 shirt which is available here from Arsenal Direct.
The transfer is subject to the completion of regulatory processes.