Brentford confirmed the deal early on Monday the January transfer window’s deadline day which runs until the end of the season.
The 29-year-old has completed his medical assessment with the Bees, having been released by Inter last month due to Italian rules on playing with an implantable cardioverter-defibrillator.
Eriksen collapsed during Denmark’s opening Euro 2020 game against Finland in June due to a cardiac arrest and has not played competitively since.
Brentford manager Thomas Frank, who worked with Eriksen at Danish youth level, said: I am looking forward to working with Christian again. He has become one of the best midfield players to appear in the Premier League. He has also won trophies all over Europe and become the star of the Danish national team.
We have taken an unbelievable opportunity to bring a World Class player to Brentford. He hasnt trained with a team for seven months but has 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 to get back towards his highest level.
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 direct free kicks.
“He is a player you can find with the ball, and he will come up with a solution to the problem in front of him. Christian will also bring experience of top level football to the Club. I expect him to have an impact in the dressing room and at the Training Ground.”
Elsewhere, Barcelona’s Ousmane Dembele appears a potential major deadline day player with Paris Saint-Germain and Manchester United interested in the French winger.
Newcastle United are expected to get busy with Matt Targett, Eddie Nketiah and Dean Henderson in their sights, while Arsenal may let Pierre-Emerick Aubameyang exit, with reports of a loan deal to Barcelona.
Everton are also expected to make up to four signings having appointed boss Frank Lampard in the past 24 hours.