The Dane last played at the most recent European Championships, where he suffered a cardiac arrest during Denmark's group stage meeting with Finland.
Frank comments on capture of world-class midfielder
Bees manager Thomas Frank spoke to the club's website to comment on the capture of the Danish international.
"I am looking forward to working with Christian again. It has been a while since I last coached him, and a lot has happened since then. Christian was 16 at the time and has become one of the best midfield players to appear in the Premier League.
"We have taken an opportunity to bring a world-class player to Brentford. He hasn't trained with a team for seven months, but has a done a lot of work on his own. He is fit, but we will need to get him match fit and I am looking forward to seeing him work with the players and staff.
"At his best, Christian has the ability to dictate games of football. He can find the right passes and is a goal threat. He also has very, very good set piece delivery, both from corners and free-kicks.
"Christian will also bring experience of top-level football to the club. I expect him to have an impact at the training ground and in the dressing room."
Giles talks process of bringing Danish international to West London
Director of football Phil Giles spoke on how the process of bringing Eriksen to west London came about.
"We first discussed the possibility of Christian joining Brentford when we heard that he would be leaving Inter. It is fantastic that he is now with us.
"Naturally the process of signing Christian was more elongated than most transfers. Brentford fans can rest assured that we have undertaken significant due diligence to ensure that Christian is in the best possible shape to return to competitive football.
"Now Christian has made the decision to sign for Brentford, all parties want to fully focus on football. We are sure that Christian will make a big impact at Brentford between now and the end of the season."