Cologne coach Christoph Daum believes the signing of Lukas Podolski from Bayern Munich is a "milestone in the history" of the club.
The Germany striker will rejoin the side he left for the Bundesliga champions in 2006 on a four-year contract in July.
The deal ends months of rumors over the future of the 23-year-old, who has grown increasingly frustrated at his lack of first-team opportunities at the Allianz Arena.
"The transfer is an absolute milestone in the history of Cologne," Daum told the city's Express newspaper. "I am looking forward to having Lukas Podolski."
The move from a club in the Champions League to one who were in the second division last term would appear to be a step down for Podolski, who has 60 caps for his country, but the frontman insists he has been sold on Cologne.
He added on the club's official website, www.fc-koeln.de: "I had very good talks with the officials and have, simply, a good feeling. The concept has convinced me - we want to build up Cologne over the coming years.
"I will be a part of the team. Cologne already has experienced players in their squad in Petit, (Milivoje) Novakovic or (Faryd) Mondragon, and added to that strong, young players like (Pedro) Geromel or (Kevin) Pezzoni are coming.
"But what role I will play in the team or which squad number I will get does not interest me at the moment - I am concentrating now on the second half of the season with Bayern."
Officials from Bayern and Cologne met in Munich last week to negotiate the protracted transfer, which had been on the cards for some months.
The main stumbling block was thought to have been the transfer fee, with Bayern holding out for 10 million euros (just over £9million), thought to be the the amount they paid for Podolski.
Details of the deal have not been widely released, but it includes a friendly match against Bayern from which it is thought the German champions will take the proceeds.
Cologne general manager Michael Meier, who had left the team's winter training camp in Belek, Turkey, early to seal the deal, said: "They were difficult negotiations, but we have, together with Bayern, found a good solution - for the player and for his future career at Cologne."
Podolski has more often than not had to settle for a place on the bench with coach Jurgen Klinsmann - as his predecessor Ottmar Hitzfeld did last season - favouring Luca Toni and Miroslav Klose up front.
He has only scored 11 times in 58 Bundesliga games in his injury-troubled time at Bayern, after netting 46 in 81 first and second-tier matches in his first spell with Cologne.
And Cologne president Wolfgang Overath claimed Podolski had "followed his heart".
"I am very pleased that Lukas is coming back to us," he said. "He has followed his heart. I am very happy about the fact that we, as a newly-promoted club, can sign a German international like Lukas Podolski."
It had looked likely he would move on last summer with Bayern chasing Stuttgart striker Mario Gomez, which would have pushed Podolski even further down the pecking order had he signed.
That deal never materialized, though, and Podolski stayed put to play under Klinsmann, with whom he had enjoyed great success for the national team.
His fortunes at the Allianz Arena, however, did not improve and reports of a possible return to Cologne quickly resurfaced.
Serie A side Roma also emerged as a possible destination, but Podolski always made it clear he preferred a return to his former club.
Podolski will meet his future team-mates when Cologne visit Munich on February 21, but Bayern general manager Uli Hoeness has no doubt the forward will give his all for the rest of the campaign.
He told the club's official website, www.fcbayern.de: "I think Lukas is, in terms of his character, a morally sound player. Therefore I believe that he will now show Bayern a certain appreciation that we have done that (agreed the transfer) for him.
"I expect that he will give everything until he goes and say goodbye to Munich in a wonderful way."
