The Blues, who signed the 21-year-old from Genk in January, had always planned to send the Belgium out on loan this summer, and he has now taken up residence at the Weserstadion.
The Belgium international's move to Stamford Bridge was confirmed during the January transfer window but he was left at Genk for the remainder of the season and only linked up with the Blues earlier this month.
However, the intention was always to loan De Bruyne out for a year and Bremen has now confirmed the 21-year-old's arrival at Weserstadion.
"We have been monitoring Kevin closely for several months have enjoyed a number of positive conversations with him and those in charge at Chelsea," CEO Klaus Allofs told the Bundesliga outfit's official website.
"We are pleased that we have been able to increase the quality in our squad with this deal."
De Bruyne, who has been capped twice by his country, came through the youth team ranks at Genk after being pried away from Gent as a teenager.
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