Swedish midfielder Freddie Ljungberg has signed with Scottish giants Celtic and could make his debut in Sunday's Old Firm derby against rivals Rangers at Ibrox.
The 33-year-old passed a medical exam on Thursday, and Celtic's website announced the signing later that day.
"I want to say that I had an amazing time in Chicago and I really mean that," Ljungberg said. "The city was great and so were the people of Chicago, who I felt embraced me in a great way. I built a strong relationship with the fans and that was something that always meant a lot to me."
Ljungberg, who joined the Chicago Fire as a Designated Player midway through last season, was out of contract after the Fire decided not to pick up his option. He had been training with Celtic all week.
"While Freddie's time with the Fire was brief, he made an immediate impact on the team both on and off the field, and we wish him the very best with Celtic FC," Chicago Fire technical director Frank Klopas said. "He's a gifted player and natural leader who quickly gained the respect of his teammates, Fire staff and our fans."
Ljungberg had a storied career at Arsenal from 1998-2007, during which he won two EPL titles and three FA Cup medals. He joined the Seattle Sounders at the beginning of their 2009 inaugural season, scoring two goals and adding nine assists en route to an appearance in the playoffs.
"I had two fantastic years in America and have seen the MLS go from strength to strength," Ljungberg said. "[I] would not trade my time there for anything in the world".
He tallied two goals and seven assists for the Fire in 15 appearances.
"I loved playing under [Chicago head coach Carlos de los Cobos], with his offensive style and beautiful passing game," Ljungberg said.
Celtic are currently top of the Scottish Premier League and sit just a single point above rivals Rangers, who have played two fewer games.
Toronto FC captain Dwayne De Rosario has also been training with Celtic, though both the club and the league have claimed they did not authorized the session.